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Components

Separate installable entities to combine in different ways to create solutions

1 - ESB3024 Router

Routes HTTP sessions to CDNs or cache nodes

1.1 - Getting Started

From requirements to a simple example

The Director serves as a versatile network service designed to redirect incoming HTTP(s) requests to the optimal host or Content Delivery Network (CDN) by evaluating various request properties through a set of rules. Although requests can be generic, the primary focus centers around audio-video content delivery. The rule engine allows users to construct routing configurations using predefined blocks, providing for the creation of intricate routing logic. This modular approach allows the users to tailor and streamline the content delivery process to meet their specific needs. The Director’s flexible rule engine takes into account factors such as geographical location, server load, content type, and other metadata from external sources to intelligently route incoming requests. It supports dynamic adjustments to seamlessly adapt to changing network conditions, ensuring efficient and reliable content delivery. The Director improves the overall user experience by delivering content from the most suitable and responsive sources, thereby reducing latency and enhancing performance.

Requirements

Hardware

The Director is designed to be installed and operated on commodity hardware, ensuring accessibility for a broad range of users. The minimum hardware specifications are as follows:

  • CPU: x86-64 AMD or Intel with at least 2 cores.
  • Memory: At least 2 GB free at runtime.

Operating System Compatibility

The Director is officially supported on Red Hat Enterprise Linux 8 (RHEL8) or any compatible operating system. While it is possible to install and run on Red Hat Enterprise Linux 7 (RHEL7) or compatible OS, this is provided as a convenience, and users should note the limited management capabilities on this platform.

External Internet access is necessary during the installation process for the installer to download and install additional dependencies. This ensures a seamless setup and optimal functionality of the Director on Red Hat Enterprise Linux 8. It’s worth noting that, due to the unique workings of the DNF package manager in Red Hat Enterprise Linux 8 with rolling package streams, an air-gapped installation process is not available.

Firewall Recommendations

See Firewall.

Installation

See Installation.

Operations

See Operations.

Configuration Process

Once the router is operational, it requires a valid configuration before it can route incoming requests.

There are currently three methods available for configuring the router, each catering to different levels of complexity. The first is a Web UI, suitable for the most common use-cases, providing an intuitive interface for configuration. The second involves utilizing a confd REST service, complemented by an optional command line tool, confcli, suitable for all but the most advanced scenarios. The third method involves leveraging an internal REST API, ideal for the most intricate cases where using confd proves to be less flexible. It’s essential to note that as the configuration method advances through these levels, both flexibility and complexity increase, providing users with tailored options based on their specific needs and expertise.

API Key Management

Regardless of the method used to configure the system, a unique API key is crucial for safeguarding the router’s configuration and preventing unauthorized access to the API. This key must be supplied when interacting with the API. During the router software installation, an automatically generated API key is created and can be located on the installed system at /opt/edgeware/acd/router/cache/rest-api-key.json. The structure of this file is as follows:

{"api_key": "abc123"}

When accessing the internal configuration API, the key must be included in the X-API-key header of the request, as shown below:

curl -v -k -H "X-API-Key: abc123" https://<router-host.example>:5001/v2/configuration

Modification to the authentication key and behavior can be done through the /v2/rest_api_key endpoint. To change the key, a PUT request with a JSON body of the same structure can be sent to the endpoint:

curl -v -k -X PUT -T new-key.json -H "X-API-Key: abc123" \
-H "Content-Type: application/json" https://<router-host.example>:5001/v2/rest_api_key

Additionally, key authentication can be disabled completely by sending a DELETE request to the endpoint:

curl -v -k -X DELETE -H "X-API-Key: abc123" \
https://<router-host.example>:5001/v2/rest_api_key

In the event of a lost or forgotten authentication key, it can always be retrieved at /opt/edgeware/acd/router/cache/rest-api-key.json on the machine running the router. It is critical to emphasize that the API key should remain private to prevent unauthorized access to the internal API, as it grants full access to the router’s configuration.

Configuration Basics

Upon completing the installation process and configuring the API keys, the subsequent section will provide guidance on configuring the router to route all incoming requests to a single host. For straightforward CDN Offload use cases, there is a web based user interface described here.

For further details on configuring the router using confd and confcli, please consult the Confd documentation.

The initial step involves defining the target host group. In this illustration, a singular group named all will be established, comprising two hosts.

$ confcli services.routing.hostGroups -w
Running wizard for resource 'hostGroups'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

hostGroups : [
  hostGroup can be one of
    1: dns
    2: host
    3: redirecting
  Choose element index or name: host
  Adding a 'host' element
    hostGroup : {
      name (default: ): all
      type (default: host):
      httpPort (default: 80):
      httpsPort (default: 443):
      hosts : [
        host : {
          name (default: ): host1.example.com
          hostname (default: ): host1.example.com
          ipv6_address (default: ):
        }
        Add another 'host' element to array 'hosts'? [y/N]: y
        host : {
          name (default: ): host2.example.com
          hostname (default: ): host2.example.com
          ipv6_address (default: ):
        }
        Add another 'host' element to array 'hosts'? [y/N]: n
      ]
    }
  Add another 'hostGroup' element to array 'hostGroups'? [y/N]: n
]
Generated config:
{
  "hostGroups": [
    {
      "name": "all",
      "type": "host",
      "httpPort": 80,
      "httpsPort": 443,
      "hosts": [
        {
          "name": "host1.example.com",
          "hostname": "host1.example.com",
          "ipv6_address": ""
        },
        {
          "name": "host2.example.com",
          "hostname": "host2.example.com",
          "ipv6_address": ""
        }
      ]
    }
  ]
}
Merge and apply the config? [y/n]:

After defining the host group, the next step is to establish a rule that directs incoming requests to the designated host. In this example, a sole rule named random will be generated, ensuring that all incoming requests are consistently routed to the previously defined host.

$ confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: random
  Adding a 'random' element
    rule : {
      name (default: ): random
      type (default: random):
      targets : [
        target (default: ): host1.example.com
        Add another 'target' element to array 'targets'? [y/N]: y
        target (default: ): host2.example.com
        Add another 'target' element to array 'targets'? [y/N]: n
      ]
    }
  Add another 'rule' element to array 'rules'? [y/N]: n
]
Generated config:
{
  "rules": [
    {
      "name": "random",
      "type": "random",
      "targets": [
        "host1.example.com",
        "host2.example.com"
      ]
    }
  ]
}
Merge and apply the config? [y/n]:

The last essential step involves instructing the router on which rule should serve as the entry point into the routing tree. In this example, we designate the rule random as the entrypoint for the routing process.

$ confcli services.routing.entrypoint random
services.routing.entrypoint = 'random'

Once this configuration is defined, all incoming requests will initiate their traversal through the routing rules, starting with the rule named random. This rule is designed to consistently match for every incoming request, effectively load balancing evenly between host1.example.com and host2.example.com on port 80 or 443, depending on whether the initial request was made using HTTP or HTTPS.

Integration with Convoy

The router is equipped with the capability to synchronize specific configuration metadata with a separate Convoy installation through the integrated convoy-bridge service. However, this service necessitates additional setup and configuration, and you can find comprehensive details on the process here..

Additional Resources

Additional documentation resources are included with the Director and can be accessed at the following directory: /opt/edgeware/acd/documentation/. This directory contains supplementary materials to provide users with comprehensive information and guidance for optimizing their experience with the Director.

Ready for Production

Once the Director software is completely installed and configured, there are a few additional considerations before moving to a full production environment. See the section Ready for Production for additional information.

1.2 - Installation

How to install and upgrade ESB3024 Router

1.2.1 - Installing release 1.12.0

How to install and upgrade to ESB3024 Router release 1.12.0

To install ESB3024 Router, one first needs to copy the installation ISO image to the target node where the router will be run. Due to the way the installer operates, it is necessary that the host is reachable by password-less SSH from itself for the user account that will perform the installation, and that this user has sudo access.

Prerequisites:

  1. Ensure that the current user has sudo access.

    sudo -l
    

    If the above command fails, you may need to add the user to the /etc/sudoers file.

  2. Ensure that the installer has password-less SSH access to localhost.

    If using the root user, the PermitRootLogin property of the /etc/ssh/sshd_config file must be set to ‘yes’.

    The local host key must also be included in the .ssh/authorized_keys file of the user running the installer. That can be done by issuing the following as the intended user:

    mkdir -m 0700 -p ~/.ssh
    ssh-keyscan localhost >> ~/.ssh/authorized_keys
    

    Note! The ssh-keyscan utility will result in the key fingerprint being output on the console. As a security best-practice its recommended to verify that this host-key matches the machine’s true SSH host key. As an alternative, to this ssh-keyscan approach, establishing an SSH connection to localhost and accepting the host key will have the same result.

  3. Disable SELinux.

    The Security-Enhanced Linux Project (SELinux) is designed to add an additional layer of security to the operating system by enforcing a set of rules on processes. Unfortunately out of the box the default configuration is not compatible with the way the installer operates. Before proceeding with the installation, it is recommended to disable SELinux. It can be re-enabled after the installation completes, if desired, but will require manual configuration. Refer to the Red Hat Customer Portal for details.

    To check if SELinux is enabled:

    getenforce
    

    This will result in one of 3 states, “Enforcing”, “Permissive” or “Disabled”. If the state is “Enforcing” use the following to disable SELinux. Either “Permissive” or “Disabled” is required to continue.

    setenforce 0
    

    This disables SELinux, but does not make the change persistent across reboots. To do that, edit the /etc/selinux/config file and set the SELINUX property to disabled.

    It is recommended to reboot the computer after changing SELinux modes, but the changes should take effect immediately.

Assuming the installation ISO image is in the current working directory, the following steps need to be executed either by root user or with sudo.

  1. Mount the installation ISO image under /mnt/acd.

    Note: The mount-point may be any accessible path, but /mnt/acd will be used throughout this document.

    mkdir -p /mnt/acd
    mount esb3024-acd-router-esb3024-1.12.0.iso /mnt/acd
    
  2. Run the installer script.

    /mnt/acd/installer
    

Upgrade from ESB3024 Router release 1.10.x

The following steps can be used to upgrade the router from release 1.10.x to 1.12.0. If upgrading from an earlier release it is recommended to perform the upgrade in multiple steps; for instance when upgrading from release 1.8.0 to 1.12.0, it is recommended to first upgrade to 1.10.1 and then to 1.12.0.

The upgrade procedure for the router is performed by taking a backup of the configuration, installing the new release of the router, and applying the saved configuration.

  1. With the router running, save a backup of the configuration.

    The exact procedure to accomplish this depends on the current method of configuration, e.g. if confd is used, then the configuration should be extracted from confd, but if the REST API is used directly, then the configuration must be saved by fetching the current configuration snapshot using the REST API.

    Extracting the configuration using confd is the recommend approach where available.

    confcli | tee config_backup.json
    

    To extract the configuration from the REST API, the following may be used instead. Depending on the version of the router used, an API-Key may be required to fetch from the REST API.

    curl --insecure https://localhost:5001/v2/configuration \
      | tee config_backup.json
    

    If the API Key is required, it can be found in the file /opt/edgeware/acd/router/cache/rest-api-key.json and can be passed to the API by setting the value of the X-API-Key header.

    curl --insecure -H "X-API-Key: 1234abcd" \
      https://localhost:5001/v2/configuration \
      | tee config_backup.json
    
  2. Mount the new installation ISO under /mnt/acd.

    Note: The mount-point may be any accessible path, but /mnt/acd will be used throughout this document.

    mkdir -p /mnt/acd
    mount esb3024-acd-router-esb3024-1.12.0.iso /mnt/acd
    
  3. Stop the router and all associated services.

    Before upgrading the router it needs to be stopped, which can be done by typing this:

    systemctl stop 'acd-*'
    
  4. Run the installer script.

    /mnt/acd/installer
    
  5. Migrate the configuration.

    Note that this step only applies if the router is configured using confd. If it is configured using the REST API, this step is not necessary.

    The confd configuration used in version 1.10.x is not directly compatible with 1.12.0, and may need to be converted. If this is not done, the configuration will not be valid and it will not be possible to make configuration changes.

    To help with migrating the configuration, a new tool has been included in the 1.12.0 release, which will automatically apply any necessary schema migrations. Further details about this tool can be found here. Confd Auto Upgrade.

    The confd-auto-upgrade tool takes as input the old configuration file, either by reading the file directly, or by reading from standard input, applies any necessary migrations between the two specified versions, and outputs a new configuration to standard output which is suitable for being applied to the upgraded system. While the tool has the ability to migrate between multiple versions at a time, the earliest supported version is 1.10.1.

    First determine the correct image name and tag for the confd-auto-upgrade image present on the node. This can be found using podman images | grep auto-upgrade. After which the configuration can be migrated using the following:

    cat config_backup.json | \
      podman run -i --rm <name>:<tag> \
      --in - --from 1.10.1 --to 1.12.0 \
      | tee config_upgraded.json
    

    Where <name> and <tag> represent the complete image name and tag from the podman images command above. Note! If multiple versions of the image are present, ensure that the version corresponding with the new release of the ACD router is used, since older versions of the tool will not contain the complete set of migrations for newer versions of the router.

    After running the above command, apply the new configuration to confd by running cat config_upgraded.json | confcli -i.

Troubleshooting

If there is a problem running the installer, additional debug information can be output by adding -v or -vv or -vvv to the installer command, the more “v” characters, the more detailed output.

1.2.1.1 - Configuration changes between 1.10.1 and 1.12.0

This describes the configuration changes between ESB3024 Router version 1.10.1 and 1.12.0.

Confd configuration changes

Below are the major changes to the confd configuration between version 1.10.1 and 1.12.0 listed.

Added services.routing.translationFunctions.session

A new translation function has been added which will allow custom Lua code to be executed after the router has made the routing decision but before generating the redirect URL.

An example use case would be for enabling instream sessions, which can be done by setting this value to return set_session_type('instream').

Removed services.routing.settins.managedSessions configuration

This configuration is no longger used.

Added services.routing.tuning.general.maxActiveManagedSessions tuning parameter.

This parameter configures the maximum number of active managed sessions.

1.2.2 - Installing release 1.10.x

How to install and upgrade to ESB3024 Router release 1.10.x

To install ESB3024 Router, one first needs to copy the installation ISO image to the target node where the router will be run. Due to the way the installer operates, it is necessary that the host is reachable by password-less SSH from itself for the user account that will perform the installation, and that this user has sudo access.

Prerequisites:

  1. Ensure that the current user has sudo access.

    sudo -l
    

    If the above command fails, you may need to add the user to the /etc/sudoers file.

  2. Ensure that the installer has password-less SSH access to localhost.

    If using the root user, the PermitRootLogin property of the /etc/ssh/sshd_config file must be set to ‘yes’.

    The local host key must also be included in the .ssh/authorized_keys file of the user running the installer. That can be done by issuing the following as the intended user:

    mkdir -m 0700 -p ~/.ssh
    ssh-keyscan localhost >> ~/.ssh/authorized_keys
    

    Note! The ssh-keyscan utility will result in the key fingerprint being output on the console. As a security best-practice its recommended to verify that this host-key matches the machine’s true SSH host key. As an alternative, to this ssh-keyscan approach, establishing an SSH connection to localhost and accepting the host key will have the same result.

  3. Disable SELinux.

    The Security-Enhanced Linux Project (SELinux) is designed to add an additional layer of security to the operating system by enforcing a set of rules on processes. Unfortunately out of the box the default configuration is not compatible with the way the installer operates. Before proceeding with the installation, it is recommended to disable SELinux. It can be re-enabled after the installation completes, if desired, but will require manual configuration. Refer to the Red Hat Customer Portal for details.

    To check if SELinux is enabled:

    getenforce
    

    This will result in one of 3 states, “Enforcing”, “Permissive” or “Disabled”. If the state is “Enforcing” use the following to disable SELinux. Either “Permissive” or “Disabled” is required to continue.

    setenforce 0
    

    This disables SELinux, but does not make the change persistent across reboots. To do that, edit the /etc/selinux/config file and set the SELINUX property to disabled.

    It is recommended to reboot the computer after changing SELinux modes, but the changes should take effect immediately.

Assuming the installation ISO image is in the current working directory, the following steps need to be executed either by root user or with sudo.

  1. Mount the installation ISO image under /mnt/acd.

    Note: The mount-point may be any accessible path, but /mnt/acd will be used throughout this document.

    mkdir -p /mnt/acd
    mount esb3024-acd-router-esb3024-1.10.1.iso /mnt/acd
    
  2. Run the installer script.

    /mnt/acd/installer
    

Upgrade from ESB3024 Router release 1.8.0

The following steps can be used to upgrade the router from release 1.8.0 to 1.10.x. If upgrading from an earlier release it is recommended to perform the upgrade in multiple steps; for instance when upgrading from release 1.6.0 to 1.10.x, it is recommended to first upgrade to 1.8.0 and then to 1.10.x.

The upgrade procedure for the router is performed by taking a backup of the configuration, installing the new release of the router, and applying the saved configuration.

  1. With the router running, save a backup of the configuration.

    The exact procedure to accomplish this depends on the current method of configuration, e.g. if confd is used, then the configuration should be extracted from confd, but if the REST API is used directly, then the configuration must be saved by fetching the current configuration snapshot using the REST API.

    Extracting the configuration using confd is the recommend approach where available.

    confcli | tee config_backup.json
    

    To extract the configuration from the REST API, the following may be used instead. Depending on the version of the router used, an API-Key may be required to fetch from the REST API.

    curl --insecure https://localhost:5001/v2/configuration \
      | tee config_backup.json
    

    If the API Key is required, it can be found in the file /opt/edgeware/acd/router/cache/rest-api-key.json and can be passed to the API by setting the value of the X-API-Key header.

    curl --insecure -H "X-API-Key: 1234abcd" \
      https://localhost:5001/v2/configuration \
      | tee config_backup.json
    
  2. Mount the new installation ISO under /mnt/acd.

    Note: The mount-point may be any accessible path, but /mnt/acd will be used throughout this document.

    mkdir -p /mnt/acd
    mount esb3024-acd-router-esb3024-1.10.1.iso /mnt/acd
    
  3. Stop the router and all associated services.

    Before upgrading the router it needs to be stopped, which can be done by typing this:

    systemctl stop 'acd-*'
    
  4. Run the installer script.

    /mnt/acd/installer
    
  5. Migrate the configuration.

    Note that this step only applies if the router is configured using confd. If it is configured using the REST API, this step is not necessary.

    The confd configuration used in version 1.8.0 is not directly compatible with 1.10.x, and may need to be converted. If this is not done, the configuration will not be valid and it will not be possible to make configuration changes.

    To determine if the configuration needs to be converted, confcli can be run like below. If it prints error messages, the configuration needs to be converted. If no error messages are printed, the configuration is valid and no further updates are necessary.

    confcli | head -n5
    [2024-04-02 14:48:37,155] [ERROR] Missing configuration key /integration
    [2024-04-02 14:48:37,162] [ERROR] Missing configuration key /services/routing/settings/qoeTracking
    [2024-04-02 14:48:37,222] [ERROR] Missing configuration key /services/routing/hostGroups/convoy-rr/hosts/convoy-rr-1/healthChecks
    [2024-04-02 14:48:37,222] [ERROR] Missing configuration key /services/routing/hostGroups/convoy-rr/hosts/convoy-rr-2/healthChecks
    [2024-04-02 14:48:37,242] [ERROR] Missing configuration key /services/routing/hostGroups/e-dns/hosts/linton-dns-1/healthChecks
    {
       "integration": {
          "convoy": {
                "bridge": {
                   "accounts": {
    

    If error messages are printed, the configuration needs to be converted. If the configuration was saved in the file config_backup.json, the conversion can be done by typing this at the command line:

    sed -E -e '/"hosts":/,/]/ s/([[:space:]]+)("hostname":.*)/\1\2\n\1"healthChecks": [],/' -e '/"apiKey":/ d' config_backup.json | \
    curl -s -X PUT -T - -H 'Content-Type: application/json' http://localhost:5000/config/__active/
    
    systemctl restart acd-confd
    

    This adds empty healthChecks sections to all hosts and removes the apiKey configuration. After that, acd-confd is restarted. See Configuration changes between 1.8.0 and 1.10.x for more details about the configuration changes.

  6. Migrating configuration to esb3024-1.10.2

    When upgrading to version 1.10.2, an extra step is required to migrate the consistent hashing configuration. This step is necessary both when upgrading from an earlier 1.10 release and when upgrading from older versions. It is only needed if consistent hashing was configured in the previous version.

    To determine if consistent hashing was configured, execute the following command:

    confcli | head -n2
    [2024-05-31 09:43:55,932] [ERROR] Missing configuration key /services/routing/rules/constantine/hashAlgorithm
    {
        "integration": {
    

    If an error message about a missing configuration key appears, the configuration must be migrated. If no such error message appears, this step should be skipped.

    To migrate the configuration, execute the following command at the command line:

    curl -s http://localhost:5000/config/__active/ | \
    sed -E 's/(.*)("type":.*"consistentHashing")(,?)/\1\2,\n\1"hashAlgorithm": "MD5"\3/' | \
    curl -s -X PUT -T - -H 'Content-Type: application/json' http://localhost:5000/config/__active/
    

    This command will read the current configuration, add the hashAlgorithm configuration key, and write back the updated configuration.

  7. Remove the Account Monitor container

    Older versions of the router installed the Account Monitor tool. This was removed in release 1.8.0, but if it is still present and unused, it can be removed by typing:

    podman rm account-monitor
    

Troubleshooting

If there is a problem running the installer, additional debug information can be output by adding -v or -vv or -vvv to the installer command, the more “v” characters, the more detailed output.

1.2.2.1 - Configuration changes between 1.8.0 and 1.10.x

This describes the configuration changes between ESB3024 Router version 1.8.0 and 1.10.x.

Confd configuration changes

Below are the major changes to the confd configuration between version 1.8.0 and 1.10.x listed.

Added integration.convoy section

An integration.convoy section has been added to the configuration. It is currently used for configuring the Convoy Bridge service.

Removed services.routing.apiKey configuration

The services.routing.apiKey configuration key has been removed. This was an obsolete way of giving the configuration access to the router. The key has to be removed from the configuration when upgrading, otherwise the configuration will not be accepted.

Added services.routing.settings.qoeTracking

A services.routing.settings.qoeTracking section has been added to the configuration.

Added healthChecks sections to the hosts

The hosts in the hostGroup entries have been extended with a healthChecks key, which is a list of functions that determine if a host is in good health.

For example, a redirecting host might look like this after the configuration has been updated:

{
    "services": {
        "routing": {
            "hostGroups": [
                {
                    "name": "convoy-rr",
                    "type": "redirecting",
                    "httpPort": 80,
                    "httpsPort": 443,
                    "forwardHostHeader": true,
                    "hosts": [
                        {
                            "name": "convoy-rr-1",
                            "hostname": "convoy-rr-1",
                            "ipv6_address": "",
                            "healthChecks": [
                                "health_check('convoy-rr-1')"
                            ]
                        }
                    ]
                }
            ],

Added hashAlgorithm to the consistentHashing rule

In esb3024-1.10.2 the consistentHashing routing rule has been extended with a hashAlgorithm key, which can have the values MD5, SDBM and Murmur. The default value is MD5.

1.2.3 - Installing release 1.8.0

How to install and upgrade to ESB3024 Router release 1.8.0

To install ESB3024 Router, one first needs to copy the installation ISO image to the target node where the router will be run. Due to the way the installer operates, it is necessary that the host is reachable by password-less SSH from itself for the user account that will perform the installation, and that this user has sudo access.

Prerequisites:

  1. Ensure that the current user has sudo access.

    sudo -l
    

    If the above command fails, you may need to add the user to the /etc/sudoers file.

  2. Ensure that the installer has password-less SSH access to localhost.

    If using the root user, the PermitRootLogin property of the /etc/ssh/sshd_config file must be set to ‘yes’.

    The local host key must also be included in the .ssh/authorized_keys file of the user running the installer. That can be done by issuing the following as the intended user:

    mkdir -m 0700 -p ~/.ssh
    ssh-keyscan localhost >> ~/.ssh/authorized_keys
    

    Note! The ssh-keyscan utility will result in the key fingerprint being output on the console. As a security best-practice its recommended to verify that this host-key matches the machine’s true SSH host key. As an alternative, to this ssh-keyscan approach, establishing an SSH connection to localhost and accepting the host key will have the same result.

  3. Disable SELinux.

    The Security-Enhanced Linux Project (SELinux) is designed to add an additional layer of security to the operating system by enforcing a set of rules on processes. Unfortunately out of the box the default configuration is not compatible with the way the installer operates. Before proceeding with the installation, it is recommended to disable SELinux. It can be re-enabled after the installation completes, if desired, but will require manual configuration. Refer to the Red Hat Customer Portal for details.

    To check if SELinux is enabled:

    getenforce
    

    This will result in one of 3 states, “Enforcing”, “Permissive” or “Disabled”. If the state is “Enforcing” use the following to disable SELinux. Either “Permissive” or “Disabled” is required to continue.

    setenforce 0
    

    It is recommended to reboot the computer after changing SELinux modes, but the changes should take effect immediately.

Assuming the installation ISO image is in the current working directory, the following steps need to be executed either by root user or with sudo.

  1. Mount the installation ISO image under /mnt/acd.

    Note: The mount-point may be any accessible path, but /mnt/acd will be used throughout this document.

    mkdir -p /mnt/acd
    mount esb3024-acd-router-esb3024-1.8.0.iso /mnt/acd
    
  2. Run the installer script.

    /mnt/acd/installer
    

Upgrade

The upgrade procedure for the router is performed by taking a backup of the configuration, installing the new version of the router, and applying the saved configuration.

  1. With the router running, save a backup of the configuration.

    The exact procedure to accomplish this depends on the current method of configuration, e.g. if confd is used, then the configuration should be extracted from confd, but if the REST API is used directly, then the configuration must be saved by fetching the current configuration snapshot using the REST API.

    Extracting the configuration using confd is the recommend approach where available.

    confcli | tee config_backup.json
    

    To extract the configuration from the REST API, the following may be used instead. Depending on the version of the router used, an API-Key may be required to fetch from the REST API.

    curl --insecure https://localhost:5001/v2/configuration \
      | tee config_backup.json
    

    If the API Key is required, it can be found in the file /opt/edgeware/acd/router/cache/rest-api-key.json and can be passed to the API by setting the value of the X-API-Key header.

    curl --insecure -H "X-API-Key: 1234abcd" \
      https://localhost:5001/v2/configuration \
      | tee config_backup.json
    
  2. Mount the new installation ISO under /mnt/acd.

    Note: The mount-point may be any accessible path, but /mnt/acd will be used throughout this document.

    mkdir -p /mnt/acd
    mount esb3024-acd-router-1.2.0.iso /mnt/acd
    
  3. Stop the router and all associated services.

    Before upgrading the router it needs to be stopped, which can be done by typing this:

    systemctl stop 'acd-*'
    
  4. Run the installer script.

    /mnt/acd/installer
    
  5. Migrate the configuration.

    Note that this step only applies if the router is configured using confd. If it is configured using the REST API, this step is not necessary.

    The confd configuration used in version 1.6.0 is not directly compatible with 1.8.0, and may need to have a few minor manual updates in order to be valid. If this is not done, the configuration will not be valid and it will not be possible to make configuration changes.

    To determine if the configuration needs to be manually updated, confcli can be run like below. If it prints error messages, the configuration needs to be updated. If no error messages are printed, the configuration is valid and no further updates are necessary.

    confcli services.routing | head
    [2024-02-01 19:05:10,769] [ERROR] Missing configuration key /services/routing/hostGroups/convoy-rr/forwardHostHeader
    [2024-02-01 19:05:10,779] [ERROR] Missing configuration key /services/routing/hostGroups/e-dns/forwardHostHeader
    [2024-02-01 19:05:10,861] [ERROR] 'forwardHostHeader'
    

    If error messages are printed, a forwardHostHeader configuration needs to be added to the hostGroups configuration. This can be done by running this at the command line:

    curl -s http://localhost:5000/config/__active/ | \
    sed -E 's/([[:space:]]+)"type": "(host|redirecting|dns)"(,?)/\1"type": "\2",\n\1"forwardHostHeader": false\3/' | \
    curl -s -X PUT -T - -H 'Content-Type: application/json' http://localhost:5000/config/__active/
    

    This reads the active configuration from the router, adds the “forwardHostHeader” configuration to all host groups, and then sends the updated configuration back to the router.

    See Configuration changes between 1.6.0 and 1.8.0 for more details about the configuration changes.

  6. Remove the Account Monitor container

    Previous versions of the router installed the Account Monitor tool. This is no longer included, but since the previous version installed, there will be a stopped Account Monitor container. If it is not used, the container can be removed by typing:

    podman rm account-monitor
    

Troubleshooting

If there is a problem running the installer, additional debug information can be output by adding -v or -vv or -vvv to the installer command, the more “v” characters, the more detailed output.

1.2.3.1 - Configuration changes between 1.6.0 and 1.8.0

This describes the configuration changes between ESB3024 Router version 1.6.0 and 1.8.0.

Confd configuration changes

Below are some of the configuration changes between version 1.4.0 and 1.6.0 listed. The list only contains the changes that might affect already existing configuration, enirely new items are not listed. Normally nothing needs to be done about this since they will be upgraded automatically, but they are listed here for reference.

Added enabled to contentPopularity

An enabled key has been added to services.routing.settings.contentPopularity. After the key has been added, the configuration looks like this:

{
    "services": {
        "routing": {
            "settings": {
                "contentPopularity": {
                    "enabled": true,
                    "algorithm": "score_based",
                    "sessionGroupNames": []
                },
                ...

Added selectionInputItemLimit to tuning

A selectionInputItemLimit key has been added to services.routing.tuning.general. After the key has been added, the configuration looks like this:

{
    "services": {
        "routing": {
            "tuning": {
                "general": {
                    ...
                    "selectionInputItemLimit": 10000,
                    ...

Added forwardHostHeader to hostGroups

All three hostGroup types (host, redirecting and dns) have been extended with a forwardHostHeader key. For example, a redirecting host might look like this after the change:

{
    "services": {
        "routing": {
            "hostGroups": [
                {
                    "name": "convoy-rr",
                    "type": "redirecting",
                    "httpPort": 80,
                    "httpsPort": 443,
                    "forwardHostHeader": true,
                    "hosts": [
                        {
                            "name": "convoy-rr-1",
                            "hostname": "convoy-rr-1",
                            "ipv6_address": ""
                        }
                    ]
                }
            ],
            ...

REST API configuration changes

The following items have been added to the REST API configuration. They will not need to be manually updated, the router will add the new keys with default values. Note that this is not a complete list of all changes, it only contains the changes that will be automatically added when upgrading the router.

If the router is configured via confd and confcli, these changes will be applied by them. This section is only relevant if the router is configured via the v2/configuration API.

  • Added the session_translation_function key.
  • Added the tuning.selection_input_item_limit key.

1.2.4 - Installing release 1.6.0

How to install and upgrade to ESB3024 Router release 1.6.0

To install ESB3024 Router, one first needs to copy the installation ISO image to the target node where the router will be run. Due to the way the installer operates, it is necessary that the host is reachable by password-less SSH from itself for the user account that will perform the installation, and that this user has sudo access.

Prerequisites:

  1. Ensure that the current user has sudo access.

    sudo -l
    

    If the above command fails, you may need to add the user to the /etc/sudoers file.

  2. Ensure that the installer has password-less SSH access to localhost.

    If using the root user, the PermitRootLogin property of the /etc/ssh/sshd_config file must be set to ‘yes’.

    The local host key must also be included in the .ssh/authorized_keys file of the user running the installer. That can be done by issuing the following as the intended user:

    mkdir -m 0700 -p ~/.ssh
    ssh-keyscan localhost >> ~/.ssh/authorized_keys
    

    Note! The ssh-keyscan utility will result in the key fingerprint being output on the console. As a security best-practice its recommended to verify that this host-key matches the machine’s true SSH host key. As an alternative, to this ssh-keyscan approach, establishing an SSH connection to localhost and accepting the host key will have the same result.

  3. Disable SELinux.

    The Security-Enhanced Linux Project (SELinux) is designed to add an additional layer of security to the operating system by enforcing a set of rules on processes. Unfortunately out of the box the default configuration is not compatible with the way the installer operates. Before proceeding with the installation, it is recommended to disable SELinux. It can be re-enabled after the installation completes, if desired, but will require manual configuration. Refer to the Red Hat Customer Portal for details.

    To check if SELinux is enabled:

    getenforce
    

    This will result in one of 3 states, “Enforcing”, “Permissive” or “Disabled”. If the state is “Enforcing” use the following to disable SELinux. Either “Permissive” or “Disabled” is required to continue.

    setenforce 0
    

    It is recommended to reboot the computer after changing SELinux modes, but the changes should take effect immediately.

Assuming the installation ISO image is in the current working directory, the following steps need to be executed either by root user or with sudo.

  1. Mount the installation ISO image under /mnt/acd.

    Note: The mount-point may be any accessible path, but /mnt/acd will be used throughout this document.

    mkdir -p /mnt/acd
    mount esb3024-acd-router-esb3024-1.8.0.iso /mnt/acd
    
  2. Run the installer script.

    /mnt/acd/installer
    

Upgrade

The upgrade procedure for the router is performed by taking a backup of the configuration, installing the new version of the router, and applying the saved configuration.

  1. With the router running, save a backup of the configuration.

    The exact procedure to accomplish this depends on the current method of configuration, e.g. if confd is used, then the configuration should be extracted from confd, but if the REST API is used directly, then the configuration must be saved by fetching the current configuration snapshot using the REST API.

    Extracting the configuration using confd is the recommend approach where available.

    confcli | tee config_backup.json
    

    To extract the configuration from the REST API, the following may be used instead. Depending on the version of the router used, an API-Key may be required to fetch from the REST API.

    curl --insecure https://localhost:5001/v2/configuration \
      | tee config_backup.json
    

    If the API Key is required, it can be found in the file /opt/edgeware/acd/router/cache/rest-api-key.json and can be passed to the API by setting the value of the X-API-Key header.

    curl --insecure -H "X-API-Key: 1234abcd" \
      https://localhost:5001/v2/configuration \
      | tee config_backup.json
    
  2. Mount the new installation ISO under /mnt/acd.

    Note: The mount-point may be any accessible path, but /mnt/acd will be used throughout this document.

    mkdir -p /mnt/acd
    mount esb3024-acd-router-1.2.0.iso /mnt/acd
    
  3. Stop the router and all associated services.

    Before upgrading the router it needs to be stopped, which can be done by typing this:

    systemctl stop 'acd-*'
    
  4. Run the installer script.

    /mnt/acd/installer
    
  5. Migrate the configuration.

    Note that this step only applies if the router is configured using confd. If it is configured using the REST API, this step is not necessary.

    See Configuration changes between 1.4.0 and 1.6.0 for instructions on how to migrate the configuration to release 1.6.0.

Troubleshooting

If there is a problem running the installer, additional debug information can be output by adding -v or -vv or -vvv to the installer command, the more “v” characters, the more detailed output.

1.2.4.1 - Configuration changes between 1.4.0 and 1.6.0

This describes the configuration changes between ESB3024 Router version 1.4.0 and 1.6.0.

confd configuration

The confd configuration used in version 1.4.0 is not directly compatible with 1.6.0, and will need to have a few minor updates in order to be valid. If this is not done, the configuration will not be valid and it will not be possible to make configuration changes. Running confcli will cause error messages and an empty default configuration to be printed.

$ confcli services.routing.
[2023-12-12 16:08:07,120] [ERROR] Missing configuration key /services/routing/translationFunctions
[2023-12-12 16:08:07,122] [ERROR] Missing configuration key /services/routing/settings/instream/dashManifestRewrite/sessionGroupNames
[2023-12-12 16:08:07,122] [ERROR] Missing configuration key /services/routing/settings/instream/hlsManifestRewrite/sessionGroupNames
[2023-12-12 16:08:07,123] [ERROR] Missing configuration key /services/routing/settings/managedSessions
[2023-12-12 16:08:07,123] [ERROR] Missing configuration key /services/routing/tuning/target/recentDurationMilliseconds
{
    "routing": {
        "apiKey": "",
        "settings": {
            "allowedProxies": [],
            "contentPopularity": {
                "algorithm": "score_based",
                "sessionGroupNames": []
            },
            "extendedContentIdentifier": {
            ...

The first thing that needs to be done is to rename the keys sessionGroupIds to sessionGroupNames. If the configuration was backed up to the file config_backup.json before upgrading, the keys can be renamed and the updated configuration can be applied by typing this:

sed 's/"sessionGroupIds"/"sessionGroupNames"/' config_backup.json | confcli -i
[2023-12-19 12:33:17,725] [ERROR] Missing configuration key /services/routing/translationFunctions
[2023-12-19 12:33:17,726] [ERROR] Missing configuration key /services/routing/settings/instream/dashManifestRewrite/sessionGroupNames
[2023-12-19 12:33:17,727] [ERROR] Missing configuration key /services/routing/settings/instream/hlsManifestRewrite/sessionGroupNames
[2023-12-19 12:33:17,727] [ERROR] Missing configuration key /services/routing/settings/managedSessions
[2023-12-19 12:33:17,727] [ERROR] Missing configuration key /services/routing/tuning/target/recentDurationMilliseconds

The configuration has not yet been converted, so the error messages are still printed. The configuration will be converted when the acd-confd service is restarted.

systemctl restart acd-confd

This concludes the conversion of the configuration and the router is ready to be used.

Configuration changes

Below are all configuration changes between version 1.4.0 and 1.6.0 listed. Normally nothing needs to be done about this since they will be upgraded automatically, but they are listed here for reference.

Added translationFunctions block

services.routing.translationFunctions has been added. It can be added as a map with two empty strings as values, to make the top of the configuration look like this:

{
    "services": {
        "routing": {
            "translationFunctions": {
                "request": "",
                "response": ""
            },
            ...

Renamed sessionGroupIds to sessionGroupNames

The keys services.routing.settings.instream.dashManifestRewrite.sessionGroupIds and services.routing.settings.instream.hlsManifestRewrite.sessionGroupIds have been renamed to services.routing.settings.instream.dashManifestRewrite.sessionGroupNames and services.routing.settings.instream.hlsManifestRewrite.sessionGroupNames respectively. Any session group IDs need to be manually converted to session group names.

After the conversion, the head of the configuration file might look like this:

{
    "services": {
        "routing": {
            "apiKey": "",
            "settings": {
                "allowedProxies": [],
                "contentPopularity": {
                    "algorithm": "score_based",
                    "sessionGroupNames": []
                },
                "extendedContentIdentifier": {
                    "enabled": false,
                    "includedQueryParams": []
                },
                "instream": {
                    "dashManifestRewrite": {
                        "enabled": false,
                        "sessionGroupNames": []
                    },
                    "hlsManifestRewrite": {
                        "enabled": false,
                        "sessionGroupNames": []
                    },
                    "reversedFilenameComparison": false
                },
                ...

Added managedSessions block

A services.routing.settings.managedSessions block has been added. After adding the block, the configuration might look like this:

{
    "services": {
        "routing": {
            "apiKey": "",
            "settings": {
                "allowedProxies": [],
                "contentPopularity": {
                    "algorithm": "score_based",
                    "sessionGroupNames": []
                },
                ...
                "managedSessions": {
                    "fraction": 0.0,
                    "maxActive": 100000,
                    "sessionTypes": []
                },
                "usageLog": {
                    "enabled": false,
                    "logInterval": 3600000
                }
            },
            ...

Added recentDurationMilliseconds

A services.routing.tuning.target.recentDurationMilliseconds key has been added to the configuration file, with a default value of 500. After adding the key, the configuration might look like this:

{
    "services": {
        "routing": {
            "apiKey": "",
            ...
            "tuning": {
                "target": {
                    ...
                    "recentDurationMilliseconds": 500,
                    ...

Storing the updated configuration

After all these changes have been done to the configuration file, it can be applied to the router using confcli.

confcli will still display error messages because the stored configuration is not valid. They will not be displayed anymore after the valid configuration has been applied.

$ confcli -i < updated_config.json
[2023-12-12 18:52:05,500] [ERROR] Missing configuration key /services/routing/translationFunctions
[2023-12-12 18:52:05,502] [ERROR] Missing configuration key /services/routing/settings/instream/dashManifestRewrite/sessionGroupNames
[2023-12-12 18:52:05,502] [ERROR] Missing configuration key /services/routing/settings/instream/hlsManifestRewrite/sessionGroupNames
[2023-12-12 18:52:05,503] [ERROR] Missing configuration key /services/routing/settings/managedSessions
[2023-12-12 18:52:05,511] [ERROR] Missing configuration key /services/routing/tuning/target/recentDurationMilliseconds

Raw configuration

The following changes have been made to the raw configuration. If the router is configured via confd and confcli, these changes will be applied by them. This section is only relevant if the router is configured via the v2/configuration API.

Simple changes

The following keys were added or removed. They will not need to be manually updated, the router will add the new keys with default values.

  • Removed the tuning.repeated_session_start_threshold_seconds key.
  • Removed the lua_paths key.
  • Added the tuning.target_recent_duration_milliseconds key.

EDNS proxy changes

If the router has been configured to use an EDNS server, the following has to be changed for the configuration to work.

The hosts.proxy_address key has been renamed to hosts.proxy_url and now accepts a port that is used when connecting to the proxy.

The cdns.http_port and cdns.https_port keys now configure the port that is used for connecting to the EDNS server, before they configured the port that is used for connecting to the proxy.

1.3 - Firewall

Firewall Configuration

For security reasons, the ESB3024 Installer does not automatically configure the local firewall to allow incoming traffic. It is the responsibility of the operations person to ensure that the system is protected from external access by placing it behind a suitable firewall solution. The following table describes the set of ports required for operation of the router.

ApplicationPortProtocolDirectionSourceDescription
Prometheus Alert Manager9093TCPINinternalMonitoring Services
Confd5000TCPINinternalConfiguration Services
Router80TCPINpublicIncoming HTTP Requests
Router443TCPINpublicIncoming HTTPS Requests
Router5001TCPINlocalhostAccess to router’s REST API
Router8000TCPINlocalhostInternal monitoring port
EDNS-Proxy8888TCPINlocalhostProxy EDNS Requests
Grafana3000TCPINinternalMonitoring Services
Grafana-Loki3100TCPINinternalLog monitoring daemon
Prometheus9090TCPINinternalMonitoring Service

The “Direction” column represents the direction in which the connection is established.

  • IN - The connection is originated from an outside server
  • OUT - The connection is established from the host to an external server.

Once a connection is established through the firewall, bidirectional traffic must be allowed using the established connection.

For the “Source” column, the following terms are used.

  • internal - Any host or network which is allowed to monitor or operate the system.
  • public - Any host or subnet that can access the router. This includes any customer network that will be making routing requests.
  • localhost - Access can be limited to local connections only.
  • any - All traffic from any source or to any destination.

Additional Ports

Convoy bridge integration

The optional convoy-bridge service needs the ability to access the Convoy MariaDB service, which by default runs on port 3306 on all of the Convoy Management servers. To allow this integration to run, port 3306/tcp must be allowed from the router to the configured Convoy Management node.

1.4 - API Overview

A brief description of the API:s served by ESB3024 Router

ESB3024 Router provides two different types of API:s:

  1. A content request API that is used by video clients to ask for content, normally using port 80 for HTTP and port 443 for HTTPS.
  2. A few REST API:s used by administrators to configure and monitor the router installation, using port 5001 over HTTPS by default.

The content API won’t be described further in this document, since it’s a simple HTTP interface serving content as regular files or redirect responses.

Raw configuration – /v2/configuration

Used to check and update the raw configuration of ESB3024 Router. Note that this API is considered an implementation detail and is not documented further.

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
GET<N/A>Success200 OKapplication/json
PUTapplication/jsonSuccess204 No Content<N/A>
PUTapplication/jsonFailure400 Bad Requestapplication/json1

Validate Configuration – /v2/validate_configuration

Used to determine if a JSON payload is correctly formatted without actually applying its configuration. A successful return status does not guarantee that the applied configuration will work, it only validates the JSON structure.

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
PUTapplication/jsonSuccess204 No Content<N/A>
PUTapplication/jsonFailure400 Bad Requestapplication/json1

Example request

When an expected field is missing from the payload, the validation will show which one and return an appropriate error message in its payload:

$ curl -i -X PUT \
    -d '{"routing": {"log_level": 3}}' \
    -H "Content-Type: application/json" \
    https://router.example:5001/v2/validate_configuration
HTTP/1.1 400 Bad Request
Access-Control-Allow-Origin: *
Content-Length: 132
Content-Type: application/json
X-Service-Identity: router.example-5fc78d

"Configuration validation: Configuration parsing failed. \
  Exception: [json.exception.out_of_range.403] (/routing) key 'id' not found"

Selection Input – /v1/selection_input

Selection input API can be used to inject external key:value data into the routing engine, making the data available when making routing decisions. An arbitrary JSON structure can be pushed to the endpoint. When performing GET or DELETE requests, specific selection input values can be accessed or deleted by including a path to the request. Note that not specifying a path will select all selection input values.

One use case for selection input is to provide data on cache availability. E.g. If you send {"edge-streamer-2-online": true} to the selection input API, you can create a routing condition eq('edge-streamer-online', true) to ensure that no traffic gets routed to the streamer if it’s offline. Note that sending the same key:value data to the selection input API will overwrite the previous value.

There is a configurable limit to how many key:value items that can be injected into the router, see the tuning parameter

$ confcli services.routing.tuning.general.selectionInputItemLimit
{
    "selectionInputItemLimit": 10000
}
REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
PUTapplication/jsonSuccess204 No Content<N/A>
PUTapplication/jsonFailure400 Bad Requestapplication/json
GET<N/A>Success200 OKapplication/json
DELETE<N/A>Success204 No Content<N/A>
DELETE<N/A>Failure404 Not Found<N/A>

Example successful request (PUT)

$ curl -i -X PUT \
    -d '{"host1_bitrate": 13000, "host1_capacity": 50000}' \
    -H "Content-Type: application/json" \
    https://router.example:5001/v1/selection_input
HTTP/1.1 204 No Content
Access-Control-Allow-Origin: *
Content-Length: 0
X-Service-Identity: router.example-5fc78d

Example unsuccessful request (PUT)

$ curl -i -X PUT \
    -d '{"cdn-status": {"session-count": 12345, "load-percent" 98}}' \
    -H "Content-Type: application/json" \
    https://router.example:5001/v1/selection_input
HTTP/1.1 400 Bad Request
Access-Control-Allow-Origin: *
Content-Length: 169
Content-Type: application/json
X-Service-Identity: router.example-5fc78d

{
  "error": "[json.exception.parse_error.101] parse error at line 1, column 57: \
    syntax error while parsing object separator - \
    unexpected number literal; expected ':'"
}

Example successful request (GET)

curl -i https://router.example:5001/v1/selection_input
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 129
Content-Type: application/json
X-Service-Identity: router.example-5fc78d

{
  "host1_bitrate": 13000,
  "host1_capacity": 50000
}

Example successful specific value request (GET)

curl -i https://router.example:5001/v1/selection_input/path/to/value
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 129
Content-Type: application/json
X-Service-Identity: router.example-5fc78d

1

Example successful request (DELETE)

curl -i -X DELETE https://router.example:5001/v1/selection_input
HTTP/1.1 204 OK
Access-Control-Allow-Origin: *
Content-Length: 129
X-Service-Identity: router.example-5fc78d

Example successful specific value request (DELETE)

curl -i -X DELETE  https://router.example:5001/v1/selection_input/value/to/delete
HTTP/1.1 204 OK
Access-Control-Allow-Origin: *
Content-Length: 129
X-Service-Identity: router.example-5fc78d

Example unsuccessful request (DELETE)

curl -i -X DELETE  https://router.example:5001/v1/selection_input/non/existent/value
HTTP/1.1 404 Not Found
Access-Control-Allow-Origin: *
Content-Length: 129
X-Service-Identity: router.example-5fc78d

Subnets – /v1/subnets

An API for managing named subnets that can be used for routing and block lists. See Subnets for more details.

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
PUTapplication/jsonSuccess204 No Content<N/A>
PUTapplication/jsonFailure400 Bad Requestapplication/json

Example request

$ curl -i -X PUT \
    -d '{"255.255.255.255/24": "test"}' \
    -H "Content-Type: application/json" \
    https://router.example:5001/v1/subnets
HTTP/1.1 204 No Content
Access-Control-Allow-Origin: *
Content-Length: 0
X-Service-Identity: router.example-5fc78d

Subrunner Resource Usage – /v1/usage

Used to monitor the load on subrunners, the processes performing those tasks that are possible to run in parallel.

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
GET<N/A>Success200 OKapplication/json

Example request

$ curl -i https://router.example:5001/v1/usage
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 1234
Content-Type: application/json
X-Service-Identity: router.example-5fc78d

{
  "total_usage": {
    "content": {
      "lru": 0,
      "newest": "-",
      "oldest": "-",
      "total": 0
    },
    "sessions": 0,
    "subrunner_usage": {
      [...]
    }
  },
  "usage_per_subrunner": [
    {
      "subrunner_usage": {
        [...]
      }
    },
    [...]
  ]
}

Metrics – /m1/v1/metrics

An interface intended to be scraped by Prometheus. It is possible to scrape it manually to see current values, but doing so will reset some counters and cause actual Prometheus data to become faulty.

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
GET<N/A>Success200 OKtext/plain

Example request

$ curl -i https://router.example:5001/m1/v1/metrics
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 1234
Content-Type: text/plain
X-Service-Identity: router.example-5fc78d

# TYPE num_configuration_changes counter
num_configuration_changes 12
# TYPE num_log_errors_total counter
num_log_errors_total 0
# TYPE num_log_warnings_total counter
num_log_warnings_total{category=""} 123
# TYPE num_log_warnings_total counter
num_log_warnings_total{category="cdn"} 0
# TYPE num_log_warnings_total counter
num_log_warnings_total{category="content"} 0
# TYPE num_log_warnings_total counter
num_log_warnings_total{category="generic"} 10
# TYPE num_log_warnings_total counter
num_log_warnings_total{category="repeated_session"} 0
# TYPE num_ssl_errors_total counter
[...]

Node Visit Counters – /v1/node_visits

Used to gather statistics about the number of visits to each node in the routing tree. The returned value is a JSON object containing node ID names and their corresponding counter values.

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
GET<N/A>Success200 OKapplication/json

See Routing Rule Evaluation Metrics for more details.

Example request

$ curl -i https://router.example:5001/v1/node_visits
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 73
Content-Type: application/json
X-Service-Identity: router.example-5fc78d

{
  "cache1.tv": "99900",
  "offload": "100"
  "routingtable": "100000"
}

Node Visit Graph – /v1/node_visits_graph

Creates a GraphML representation of the node visitation data that can be rendered into an image to make it easier to understand the data.

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
GET<N/A>Success200 OKapplication/xml

See Routing Rule Evaluation Metrics for more details.

Example request

> curl -i -k https://router.example:5001/v1/node_visits_graph
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 731
Content-Type: application/xml
X-Service-Identity: router.example-5fc78d

<?xml version="1.0"?>
<graphml xmlns="http://graphml.graphdrawing.org/xmlns"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
  <key id="visits" for="node" attr.name="visits" attr.type="string" />
  <graph id="G" edgedefault="directed">
    <node id="routingtable">
      <data key="visits">100000</data>
    </node>
    <node id="cache1.tv">
      <data key="visits">99900</data>
    </node>
    <node id="offload">
      <data key="visits">100</data>
    </node>
    <edge id="e0" source="routingtable" target="cache1.tv" />
    <edge id="e1" source="routingtable" target="offload" />
  </graph>
</graphml>

Session list - /v1/sessions

Used to monitor the load on subrunners, the processes performing those tasks that are possible to run in parallel.

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
GET<N/A>Success200 OKapplication/json

Example request

$ curl -k -i https://router.example:5001/v1/sessions
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 12345
Content-Type: application/json
X-Service-Identity: router.example-5fc78d

{
  "sessions": [
    {
      "age_seconds": 103,
      "cdn": "edgeware",
      "cdn_is_redirecting": false,
      "client_ip": "1.2.3.4",
      "host": "cdn.example:80",
      "id": "router.example-5fc78d-00000001",
      "idle_seconds": 103,
      "last_request_time": "2022-12-02T14:05:05Z",
      "latest_request_path": "/__cl/s:storage1/__c/v/f/0/5/v_sintel3v_f05a05f07d352e891d79863131ef4df7/__op/hls-default/__f/index.m3u8",
      "no_of_requests": 1,
      "requested_bytes": 0,
      "requests_redirected": 0,
      "requests_served": 0,
      "session_groups": [
        "all"
      ],
      "session_groups_generation": 2,
      "session_path": "/__cl/s:storage1/__c/v/f/0/5/v_sintel3v_f05a05f07d352e891d79863131ef4df7/__op/hls-default/__f/index.m3u8",
      "start_time": "2022-12-02T14:05:05Z",
      "type": "instream",
      "user_agent": "libmpv"
    },
    [...]
  ]
}

Session details - /v1/sessions/<id: str>

Used to get details about a specific session from the above session list. The id part of the URL corresponds to the id field in one of the returned session entries in the above response.

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
GET<N/A>Success200 OKapplication/json
GET<N/A>Failure404 Not Foundapplication/json

Example request

$ curl -k -i https://router.example:5001/v1/sessions/router.example-5fc78d-00000001
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 763
Content-Type: application/json
X-Service-Identity: router.example-5fc78d

{
  "age_seconds": 183,
  "cdn": "edgeware",
  "cdn_is_redirecting": false,
  "client_ip": "1.2.3.4",
  "host": "cdn.example:80",
  "id": "router.example-5fc78d-00000001",
  "idle_seconds": 183,
  "last_request_time": "2022-12-02T14:05:05Z",
  "latest_request_path": "/__cl/s:storage1/__c/v/f/0/5/v_sintel3v_f05a05f07d352e891d79863131ef4df7/__op/hls-default/__f/index.m3u8",
  "no_of_requests": 1,
  "requested_bytes": 0,
  "requests_redirected": 0,
  "requests_served": 0,
  "session_groups": [
    "all"
  ],
  "session_groups_generation": 2,
  "session_path": "/__cl/s:storage1/__c/v/f/0/5/v_sintel3v_f05a05f07d352e891d79863131ef4df7/__op/hls-default/__f/index.m3u8",
  "start_time": "2022-12-02T14:05:05Z",
  "type": "instream",
  "user_agent": "libmpv"
}

Content List - /v1/content

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
GET<N/A>Success200 OKapplication/json

Example request

$ curl -k -i https://router.example:5001/v1/content
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 572
Content-Type: application/json
X-Service-Identity: router.example-5fc78d

{
  "content": [
    [
      "/__cl/s:storage1/__c/v/f/0/5/v_sintel3v_f05a05f07d352e891d79863131ef4df7/__op/hls-default/__f/index.m3u8",
      {
        "cached_count": 0,
        "content_requested": false,
        "content_set": false,
        "expiration_time": "2022-12-02T14:05:05Z",
        "key": "/__cl/s:storage1/__c/v/f/0/5/v_sintel3v_f05a05f07d352e891d79863131ef4df7/__op/hls-default/__f/index.m3u8",
        "listeners": 0,
        "manifest": "",
        "request_count": 4,
        "state": "HLS:MANIFEST-PENDING",
        "wait_count": 0
      }
    ]
  ]
}

Lua scripts – /v1/lua/<path str>.lua

Used to upload, retrieve and delete custom named Lua scripts on the router. Global functions in uploaded scripts automatically become available to Lua code in the configuration (which effectively may be viewed as hooks). Upload a script by PUTing a application/x-lua to the endpoint, and retrieve it by GETing the endpoint without payload.

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
PUTapplication/x-luaSuccess204 No Content<N/A>
PUTapplication/x-luaFailure400 Bad Requestapplication/json
GET<N/A>Success200 OKapplication/x-lua
GET<N/A>Failure404 Not Foundapplication/json
DELETE<N/A>Success204 No Content<N/A>
DELETE<N/A>Failure400 Bad Requestapplication/json
DELETE<N/A>Failure404 Not Foundapplication/json

Example request (PUT)

Save a Lua script under the name advanced_functions/f1.lua:

$ curl -i -X PUT \
    -d 'function fun1() return 1 end' \
    -H "Content-Type: application/x-lua" \
    https://router.example:5001/v1/lua/advanced_functions/f1.lua
HTTP/1.1 204 Successfully saved Lua file
Access-Control-Allow-Origin: *
Content-Length: 0
X-Service-Identity: router.example-5fc78d

Example request (PUT, from file)

Upload an entire Lua file under the name advanced_functions/f1.lua:

First put your code in a file.

$ cat f1.lua
function fun1()
    return 1
end

Then upload it using the --data-binary flag to preserve newlines

$ curl -i -X PUT \
    --data-binary @f1.lua \
    -H "Content-Type: application/x-lua" \
    https://router.example:5001/v1/lua/advanced_functions/f1.lua
HTTP/1.1 204 Successfully saved Lua file
Access-Control-Allow-Origin: *
Content-Length: 0
X-Service-Identity: router.example-5fc78d

Example request (GET)

Request the Lua script named advanced_functions/f1.lua using a GET request:

$ curl -i https://router.example:5001/v1/lua/advanced_functions/f1.lua
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 28
Content-Type: application/x-lua
X-Service-Identity: router.example-5fc78d

function fun1() return 1 end

Example request (DELETE)

Delete the Lua script named advanced_functions/f1.lua using a DELETE request:

$ curl -i -X DELETE \
    https://router.example:5001/v1/lua/advanced_functions/f1.lua
HTTP/1.1 204 Successfully removed Lua file
Access-Control-Allow-Origin: *
Content-Length: 0
X-Service-Identity: router.example-5fc78d

List Lua scripts – /v1/lua

Used to list previously uploaded custom Lua scripts on the router, retrieving their respective paths and file checksums.

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
GET<N/A>Success200 OKapplication/json

Example request

$ curl -k -i https://router.example:5001/v1/lua
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 108
Content-Type: application/json
X-Service-Identity: router.example-5fc78d

[
  {
    "file_checksum": "d41d8cd98f00b204e9800998ecf8427e",
    "path": "advanced_functions/f1.lua"
  }
]

Debug a Lua expression – /v1/lua/debug

Used to debug an arbitrary Lua expression on the router in a “sandbox” (with no visible side effects to the state of the router), and inspect the result.

The Lua expression in the body is evaluated inside an isolated copy of the internal Lua environment including selection input. The stdout field of the resulting JSON body is populated with a concatenation of every string provided as argument to the Lua print() function during the course of evaluation. Upon a successful evaluation, as indicated by the success flag, return.value and return.lua_type_name capture the resulting Lua value. Otherwise, if valuation was aborted (e.g. due to a Lua exception), error_msg reflects any error description arising from the Lua environment.

REQUEST
Method
Content-TypeRESPONSE
Result
Status CodeContent-Type
POSTapplication/x-luaSuccess200 OKapplication/json

Example successful request

$ curl -i -X POST \
    -d 'fun1()' \
    -H "Content-Type: application/x-lua" \
    https://router.example:5001/v1/lua/debug
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 123
Content-Type: application/json
X-Service-Identity: router.example-5fc78d

{
  "error_msg": "",
  "return": {
    "lua_type_name": "number",
    "value": 1.0
  },
  "stdout": "",
  "success": true
}

Example unsuccessful request

(attempt to invoke unknown function)

$ curl -i -X POST \
    -d 'fun5()' \
    -H "Content-Type: application/x-lua" \
    https://router.example:5001/v1/lua/debug
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Length: 123
Content-Type: application/json
X-Service-Identity: router.example-5fc78d

{
  "error_msg": "[string \"function f0() ...\"]:2: attempt to call global 'fun5' (a nil value)",
  "return": {
    "lua_type_name": "",
    "value": null
  },
  "stdout": "",
  "success": false
}

Access logging

When the configuration parameter tuning.access_log is set to true, HTTP requests are logged in the common log format (see https://en.wikipedia.org/wiki/Common_Log_Format) and tagged with the matchable field "ACCESSLOG=1" to be retrieved with journalctl:

journalctl SYSLOG_IDENTIFIER=router ACCESSLOG=1

Example output

-- Logs begin at Tue 2023-05-23 07:57:16 UTC, end at Mon 2023-05-29 07:25:59 UTC. --
May 29 07:20:00 router[52236]: ::1 - - [29/May/2023:07:20:00 +0000] "GET /vod/batman.m3u8 HTTP/1.1" 302 0 "-" "curl/7.61.1"

Some useful optional arguments to journalctl are:

journalctl SYSLOG_IDENTIFIER=router ACCESSLOG=1 [--follow] [-o json-pretty] [--since 2022-06-06] [--until 2022-06-10]
[--grep="HTTP/1.1\" 404"]

See the journalctl documentation for further reading.

Footnotes


  1. The content type of the response is set to “application/json” but the payload is actually a regular string without JSON syntax. ↩︎ ↩︎

1.5 - Configuration

How to write and deploy configuration for ESB3024 Router

1.5.1 - WebUI Configuration

How to use the web user interface for configuration.

The web based user interface is installed as a separate component and can be used to configure many common use cases. After navigating to the UI, a login screen will be presented.

Login Screen

Enter your credentials and log in. In the top left corner is a menu to select what section of the configuration to change. The configuration that will be active on the router is added in the Routing Workflow view. However, basic elements such as classification rules and routing targets, etc must be added first. Hence the following main steps are required to produce a proper configuration:

  1. Create classifiers serving as basic elements to create session groups.
  2. Create session groups which, using the classifiers, tag requests/clients for later use in the routing logic. of the incoming traffic.
  3. Define offload rules.
  4. Define rules to control behavior of internal traffic.
  5. Define backup rules to be used if the routing targets in the above step are unavailable.
  6. Finally, create the desired routing workflow using the elements defined in the previous steps.

A simplified concrete example of the above steps could be:

  • Create two classifiers “smartphone” and “off-net”.
  • Create a session group “mobile off-net”.
  • Offload off-net traffic from mobile phones to a public CDN.
  • Route other traffic to a private CDN.
  • If the private CDN has an outage, use the public CDN for all traffic.

Hence, to start with, define the classifiers you will need. Those are based on information in the incoming request, optionally in combination with GeoIP databases or subnet information configured via the Subnet API. Here we show how to set up a GeoIP classifier. Note that the Director ships with a compatible snapshot of the GeoIP database, but for a production system a licensed and updated database is required.

GeoIP Classifier

Click the plus sign indicated in the picture above to create a new GeoIP classifier. You will be presented with the following view:

GeoIP Classifier Create

Here you can enter the geographical data on which to match, or check the “Inverted” check box to match anything except the entered geographical data.

The other kinds of classifiers are configured in a similar way.

After having added all the classifiers you need, it is time to create the session groups. Those are named filters that group incoming requests, typically video playback sessions in a video streaming CDN, and are defined with the help of the classifiers. For example, a session group “off-net mobile devices” could be composed of the classifiers “off-net traffic” and “mobile devices”.

Open the Session Groups view from the menu and hit the plus sign to add a new session group.

Session Groups Session Group Create

Define the new sessions groups by combining the previously created classifiers. It is often convenient to define an “All” session group that matches any incoming request.

Next go the “CDN Offload” view:

CDN Offload

Here you define conditions for CDN offload. Each row defines a rule for offloading a specified session group. The rule makes use of the Selection Input API. This is an integration API that provides a way to supply additional data for use in the routing decision. Common examples are current bitrates or availability status. The selection input variables to use must be defined in the “Selection Input Types” view in the “Administration” section of the menu:

Selection Input Types

Reach out to the solution engineers from Agile Content in order to perform this integration in the best way. If no external data is required, such that the offload rule can be based solely based on session groups, this is not necessary and the condition field can be set to “Always” or “Disabled”.

When clicking the plus sign to add a new CDN Offload rule, the following view is presented:

CDN Offload Create

The selection input rule is phrased in terms of a variable being above or below a threshold, but also a state such as “available” taking values 0 or 1 can be supported by for instance checking if “available” is below 1.

Moving on, if an incoming request is not offloaded, it will be handled by the Primary CDN section of the routing configuration.

Primary CDN

Add all hosts in your primary CDN, together with a weight. A row in this table will be selected by random weighted load balancing. If each weight is the same, each row will be selected with the same probability. Another example would be three rows with weights 100, 100 and 200 which would randomly balance 50% of the load on the last row and the remaining load on the first two rows, i.e. 25% on each of the first and second row. If a Primary CDN host is unavailable, that host will not take part in the random selection.

If all hosts are unavailable, as a final resort the routing evaluation will go to the final Backup CDN step:

Backup CDN

Here you can define what to do when all else fail. If not all requests are covered, for example with an “All” session group, then the request will fail with 403 Forbidden.

Now you have defined the basic elements and it is time to define the routing workflow. Select “Routing Workflow” from the menu, as pictured below. Here you can combine the elements previously created to achieve the desired routing behavior.

Routing Workflow

When everything seems correct, open the “Publish Routing” view from the menu:

Publish Routing

Hit “Publish All Changes” and verify that you get a successful result.

1.5.2 - Confd and Confcli

Using the command line tool confcli to set up routing rules

Configuration of a complex routing tree can be difficult. The command line interface tool called confcli has been developed to make it simpler. It combines building blocks, representing simple routing decisions, into complex routing trees capable of satisfying almost any routing requirements.

These blocks are translated into an ESB3024 Router configuration which is automatically sent to the router, overwriting existing routing rules, CDN list and host list.

Installation and Usage

The confcli tools are installed alongside ESB3024 Router, on the same host, and the confcli command line tool itself is made available on the host machine.

Simply type confcli in a shell on the host to see the current routing configuration:

$ confcli
{
    "services": {
        "routing": {
            "settings": {
                "allowedProxies": [],
                "contentPopularity": {
                    "algorithm": "score_based",
                    "sessionGroupNames": []
                },
                "extendedContentIdentifier": {
                    "enabled": false,
                    "includedQueryParams": []
                },
                "instream": {
                    "dashManifestRewrite": {
                        "enabled": false,
                        "sessionGroupNames": []
                    },
                    "hlsManifestRewrite": {
                        "enabled": false,
                        "sessionGroupNames": []
                    },
                    "reversedFilenameComparison": false
                },
                "usageLog": {
                    "enabled": false,
                    "logInterval": 3600000
                }
            },
            "tuning": {
                "content": {
                    "cacheSizeFullManifests": 1000,
                    "cacheSizeLightManifests": 10000,
                    "lightCacheTimeMilliseconds": 86400000,
                    "liveCacheTimeMilliseconds": 100,
                    "vodCacheTimeMilliseconds": 10000
                },
                "general": {
                    "accessLog": false,
                    "coutFlushRateMilliseconds": 1000,
                    "cpuLoadWindowSize": 10,
                    "eagerCdnSwitching": false,
                    "httpPipeliningEnable": false,
                    "logLevel": 3,
                    "maxConnectionsPerHost": 5,
                    "overloadThreshold": 32,
                    "readyThreshold": 8,
                    "redirectingCdnManifestDownloadRetries": 2,
                    "repeatedSessionStartThresholdSeconds": 30,
                    "selectionInputMetricsTimeoutSeconds": 30
                },
                "session": {
                    "idleDeactivateTimeoutMilliseconds": 20000,
                    "idleDeleteTimeoutMilliseconds": 1800000
                },
                "target": {
                    "responseTimeoutSeconds": 5,
                    "retryConnectTimeoutSeconds": 2,
                    "retryResponseTimeoutSeconds": 2,
                    "connectTimeoutSeconds": 5,
                    "maxIdleTimeSeconds": 30,
                    "requestAttempts": 3
                }
            },
            "sessionGroups": [],
            "classifiers": [],
            "hostGroups": [],
            "rules": [],
            "entrypoint": "",
            "applyConfig": true
        }
    }
}

The CLI tool can be used to modify, add and delete values by providing it with the “path” to the object to change. The path is constructed by joining the field names leading up to the value with a period between each name, e.g. the path to the entrypoint is services.routing.entrypoint since entrypoint is nested under the routing object, which in turn is under the services root object. Lists use an index number in place of a field name, where 0 indicates the very first element in the list, 1 the second element and so on.

If the list contains objects which have a field with the name name, the index number can be replaced by the unique name of the object of interest.

Tab completion is supported by confcli. Pressing tab once will complete as far as possible, and pressing tab twice will list all available alternatives at the path constructed so far.

Display the values at a specific path:

$ confcli services.routing.hostGroups
{
    "hostGroups": [
        {
            "name": "internal",
            "type": "redirecting",
            "httpPort": 80,
            "httpsPort": 443,
            "hosts": [
                {
                    "name": "rr1",
                    "hostname": "rr1.example.com",
                    "ipv6_address": ""
                }
            ]
        },
        {
            "name": "external",
            "type": "host",
            "httpPort": 80,
            "httpsPort": 443,
            "hosts": [
                {
                    "name": "offload-streamer1",
                    "hostname": "streamer1.example.com",
                    "ipv6_address": ""
                },
                {
                    "name": "offload-streamer2",
                    "hostname": "streamer2.example.com",
                    "ipv6_address": ""
                }
            ]
        }
    ]
}

Display the values in a specific list index:

$ confcli services.routing.hostGroups.1
{
    "1": {
        "name": "external",
        "type": "host",
        "httpPort": 80,
        "httpsPort": 443,
        "hosts": [
            {
                "name": "offload-streamer1",
                "hostname": "streamer1.example.com",
                "ipv6_address": ""
            },
            {
                "name": "offload-streamer2",
                "hostname": "streamer2.example.com",
                "ipv6_address": ""
            }
        ]
    }
}

Display the values in a specific list index using the object’s name:

$ confcli services.routing.hostGroups.1.hosts.offload-streamer2
{
    "offload-streamer2": {
        "name": "offload-streamer2",
        "hostname": "streamer2.example.com",
        "ipv6_address": ""
    }
}

Modify a single value:

confcli services.routing.hostGroups.1.hosts.offload-streamer2.hostname new-streamer.example.com
services.routing.hostGroups.1.hosts.offload-streamer2.hostname = 'new-streamer.example.com'

Delete an entry:

$ confcli services.routing.sessionGroups.Apple.classifiers.
{
    "classifiers": [
        "Apple",
        ""
    ]
}

$ confcli services.routing.sessionGroups.Apple.classifiers.1 -d
http://localhost:5000/config/__active/services/routing/sessionGroups/Apple/classifiers/1 reset to default/deleted

$ confcli services.routing.sessionGroups.Apple.classifiers.
{
    "classifiers": [
        "Apple"
    ]
}

Adding new values in objects and lists is done using a wizard by invoking confcli with a path and the -w argument. This will be shown extensively in the examples further down in this document rather than here.

If you have a JSON file with a previously generated confcli configuration output it can be applied to a system by typing confcli -i <file path>.

CDNs and Hosts

Configuration using confcli has no real concept of CDNs, instead it has groups of hosts that share some common settings such as HTTP(S) port and whether they return a redirection URL, serve content directly or perform a DNS lookup. Of these three variants, the two former share the same parameters, while the DNS variant is slightly different.

Each host belongs to a host group and may itself be an entire CDN using a single public hostname or a single streamer server, all depending on the needs of the user.

Host Health

When creating a host in the confd configuration, you have the option to define a list of health check functions. Each health check function must return true for a host to be selected. This means that the host will only be considered available if all the defined health check functions evaluate to true. If any of the health check functions return false, the host will be considered unavailable and will not be selected for routing. All health check functions are detailed in the section Health Check Functions.

$ confcli services.routing.hostGroups -w
Running wizard for resource 'hostGroups'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

hostGroups : [
  hostGroup can be one of
    1: dns
    2: host
    3: redirecting
  Choose element index or name: redirecting
  Adding a 'redirecting' element
    hostGroup : {
      name (default: ): edgeware
      type (default: redirecting): ⏎
      httpPort (default: 80): ⏎
      httpsPort (default: 443): ⏎
      hosts : [
        host : {
          name (default: ): rr1
          hostname (default: ): convoy-rr1.example.com
          ipv6_address (default: ): ⏎
          healthChecks : [
            healthCheck (default: always()): basic_health_check()
            Add another 'healthCheck' element to array 'healthChecks'? [y/N]: n
          ]
        }
        Add another 'host' element to array 'hosts'? [y/N]: y
        host : {
          name (default: ): rr2
          hostname (default: ): convoy-rr2.example.com
          ipv6_address (default: ): ⏎
          healthChecks : [
            healthCheck (default: always()): ⏎
            Add another 'healthCheck' element to array 'healthChecks'? [y/N]: n
          ]
        }
        Add another 'host' element to array 'hosts'? [y/N]: ⏎
      ]
    }
  Add another 'hostGroup' element to array 'hostGroups'? [y/N]: ⏎
]
Generated config:
{
  "hostGroups": [
    {
      "name": "edgeware",
      "type": "redirecting",
      "httpPort": 80,
      "httpsPort": 443,
      "hosts": [
        {
          "name": "rr1",
          "hostname": "convoy-rr1.example.com",
          "ipv6_address": "",
          "healthChecks": [
            "basic_health_check()"
          ]
        },
        {
          "name": "rr2",
          "hostname": "convoy-rr2.example.com",
          "ipv6_address": "",
          "healthChecks": [
            "always()"
          ]
        }
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.hostGroups -w
Running wizard for resource 'hostGroups'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

hostGroups : [
  hostGroup can be one of
    1: dns
    2: host
    3: redirecting
  Choose element index or name: dns
  Adding a 'dns' element
    hostGroup : {
      name (default: ): external-dns
      type (default: dns): ⏎
      hosts : [
        host : {
          name (default: ): dns-host
          hostname (default: ): dns.example.com
          ipv6_address (default: ): ⏎
          healthChecks : [
            healthCheck (default: always()): ⏎
            Add another 'healthCheck' element to array 'healthChecks'? [y/N]: n
          ]
        }
        Add another 'host' element to array 'hosts'? [y/N]: ⏎
      ]
    }
  Add another 'hostGroup' element to array 'hostGroups'? [y/N]: ⏎
]
Generated config:
{
  "hostGroups": [
    {
      "name": "external-dns",
      "type": "dns",
      "hosts": [
        {
          "name": "dns-host",
          "hostname": "dns.example.com",
          "ipv6_address": "",
          "healthChecks": [
            "always()"
          ]
        }
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y
  

Rule Blocks

The routing configuration using confcli is done using a combination of logical building blocks, or rules. Each block evaluates the incoming request in some way and sends it on to one or more sub-blocks. If the block is of the host type described above, the client is sent to that host and the evaluation is done.

Existing blocks

Currently supported blocks are:

  • allow: Incoming requests, for which a given rule function matches, are immediately sent to the provided onMatch target.
  • consistentHashing: Splits incoming requests randomly between preferred hosts, determined by the proprietary consistent hashing algorithm. The amount of hosts to split between is controlled by the spreadFactor.
  • contentPopularity: Splits incoming requests into two sub-blocks depending on how popular the requested content is.
  • deny: Incoming requests, for which a given rule function matches, are immediately denied, and all non-matching requests are sent to the onMiss target.
  • firstMatch: Incoming requests are matched by an ordered series of rules, where the request will be handled by the first rule for which the condition evaluates to true.
  • random: Splits incoming requests randomly and equally between a list of target sub-blocks. Useful for simple load balancing.
  • split: Splits incoming requests between two sub-blocks depending on how the request is evaluated by a provided function. Can be used for sending clients to different hosts depending on e.g. geographical location or client hardware type.
  • weighted: Randomly splits incoming requests between a list of target sub-blocks, weighted according to each target’s associated weight rule. A higher weight means a higher portion of requests will be routed to a sub-block. Rules can be used to decide whether or not to pick a target.
  • rawGroup: Contains a raw ESB3024 Router configuration routing tree node, to be inserted as is in the generated configuration. This is only meant to be used in the rare cases when it’s impossible to construct the required routing behavior in any other way.
  • rawHost: A host reference for use as endpoints in rawGroup trees.
$ confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: allow
  Adding a 'allow' element
    rule : {
      name (default: ): allow
      type (default: allow): ⏎
      condition (default: ): customFunction()
      onMatch (default: ): rr1
    }
  Add another 'rule' element to array 'rules'? [y/N]: ⏎
]
Generated config:
{
  "rules": [
    {
      "name": "content",
      "type": "contentPopularity",
      "condition": "customFunction()",
      "onMatch": "rr1"
    }
  ]
}
Merge and apply the config? [y/n]: y
$ confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: consistentHashing
  Adding a 'consistentHashing' element
    rule : {
      name (default: ): consistentHashingRule
      type (default: consistentHashing): 
      spreadFactor (default: 1): 2
      hashAlgorithm (default: MD5):
      targets : [
        target : {
          target (default: ): rr1
          enabled (default: True): 
        }
        Add another 'target' element to array 'targets'? [y/N]: y
        target : {
          target (default: ): rr2
          enabled (default: True): 
        }
        Add another 'target' element to array 'targets'? [y/N]: y
        target : {
          target (default: ): rr3
          enabled (default: True): 
        }
        Add another 'target' element to array 'targets'? [y/N]: n
      ]
    }
  Add another 'rule' element to array 'rules'? [y/N]: n
]
Generated config:
{
  "rules": [
    {
      "name": "consistentHashingRule",
      "type": "consistentHashing",
      "spreadFactor": 2,
      "hashAlgorithm": "MD5",
      "targets": [
        {
          "target": "rr1",
          "enabled": true
        },
        {
          "target": "rr2",
          "enabled": true
        },
        {
          "target": "rr3",
          "enabled": true
        }
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y
$ confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: contentPopularity
  Adding a 'contentPopularity' element
    rule : {
      name (default: ): content
      type (default: contentPopularity): ⏎
      contentPopularityCutoff (default: 10): 20
      onPopular (default: ): rr1
      onUnpopular (default: ): rr2
    }
  Add another 'rule' element to array 'rules'? [y/N]: ⏎
]
Generated config:
{
  "rules": [
    {
      "name": "content",
      "type": "contentPopularity",
      "contentPopularityCutoff": 20.0,
      "onPopular": "rr1",
      "onUnpopular": "rr2"
    }
  ]
}
Merge and apply the config? [y/n]: y
$ confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: deny
  Adding a 'deny' element
    rule : {
      name (default: ): deny
      type (default: deny): ⏎
      condition (default: ): customFunction()
      onMiss (default: ): rr1
    }
  Add another 'rule' element to array 'rules'? [y/N]: ⏎
]
Generated config:
{
  "rules": [
    {
      "name": "content",
      "type": "contentPopularity",
      "condition": "customFunction()",
      "onMiss": "rr1"
    }
  ]
}
Merge and apply the config? [y/n]: y
$ confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: firstMatch
  Adding a 'firstMatch' element
    rule : {
      name (default: ): firstMatch
      type (default: firstMatch): ⏎
      targets : [
        target : {
          onMatch (default: ): rr1
          rule (default: ): customFunction()
        }
        Add another 'target' element to array 'targets'? [y/N]: y
        target : {
          onMatch (default: ): rr2
          rule (default: ): otherCustomFunction()
        }
        Add another 'target' element to array 'targets'? [y/N]: n
      ]
    }
  Add another 'rule' element to array 'rules'? [y/N]: n
]
Generated config:
{
  "rules": [
    {
      "name": "firstMatch",
      "type": "firstMatch",
      "targets": [
        {
          "onMatch": "rr1",
          "condition": "customFunction()"
        },
        {
          "onMatch": "rr2",
          "condition": "otherCustomFunction()"
        }
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y
$ confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: random
  Adding a 'random' element
    rule : {
      name (default: ): random
      type (default: random): ⏎
      targets : [
        target (default: ): rr1
        Add another 'target' element to array 'targets'? [y/N]: y
        target (default: ): rr2
        Add another 'target' element to array 'targets'? [y/N]: ⏎
      ]
    }
  Add another 'rule' element to array 'rules'? [y/N]: ⏎
]
Generated config:
{
  "rules": [
    {
      "name": "random",
      "type": "random",
      "targets": [
        "rr1",
        "rr2"
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: split
  Adding a 'split' element
    rule : {
      name (default: ): split
      type (default: split): ⏎
      condition (default: ): custom_function()
      onMatch (default: ): rr2
      onMiss (default: ): rr1
    }
  Add another 'rule' element to array 'rules'? [y/N]: ⏎
]
Generated config:
{
  "rules": [
    {
      "name": "split",
      "type": "split",
      "condition": "custom_function()",
      "onMatch": "rr2",
      "onMiss": "rr1"
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.rules. -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: weighted
  Adding a 'weighted' element
    rule : {
      name (default: ): weight
      type (default: weighted): ⏎
      targets : [
        target : {
          target (default: ): rr1
          weight (default: 100): ⏎
          condition (default: always()): always()
        }
        Add another 'target' element to array 'targets'? [y/N]: y
        target : {
          target (default: ): rr2
          weight (default: 100): si('rr2-input-weight')
          condition (default: always()): gt('rr2-bandwidth', 1000000)
        }
        Add another 'target' element to array 'targets'? [y/N]: y
        target : {
          target (default: ): rr2
          weight (default: 100): custom_func()
          condition (default: always()): always()
        }
        Add another 'target' element to array 'targets'? [y/N]: ⏎
      ]
    }
  Add another 'rule' element to array 'rules'? [y/N]: ⏎
]
Generated config:
{
  "rules": [
    {
      "name": "weight",
      "type": "weighted",
      "targets": [
        {
          "target": "rr1",
          "weight": "100",
          "condition": "always()"
        },
        {
          "target": "rr2",
          "weight": "si('rr2-input-weight')",
          "condition": "gt('rr2-bandwith', 1000000)"
        },
        {
          "target": "rr2",
          "weight": "custom_func()",
          "condition": "always()"
        }
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y
  
>> First add a raw host block that refers to a regular host

$ confcli services.routing.rules. -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: rawHost
  Adding a 'rawHost' element
    rule : {
      name (default: ): raw-host
      type (default: rawHost): ⏎
      hostId (default: ): rr1
    }
  Add another 'rule' element to array 'rules'? [y/N]: ⏎
]
Generated config:
{
  "rules": [
    {
      "name": "raw-host",
      "type": "rawHost",
      "hostId": "rr1"
    }
  ]
}
Merge and apply the config? [y/n]: y

>> And then add a rule using the host node

$ confcli services.routing.rules. -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: rawGroup
  Adding a 'rawGroup' element
    rule : {
      name (default: ): raw-node
      type (default: rawGroup): ⏎
      memberOrder (default: sequential): ⏎
      members : [
        member : {
          target (default: ): raw-host
          weightFunction (default: ): return 1
        }
        Add another 'member' element to array 'members'? [y/N]: ⏎
      ]
    }
  Add another 'rule' element to array 'rules'? [y/N]: ⏎
]
Generated config:
{
  "rules": [
    {
      "name": "raw-node",
      "type": "rawGroup",
      "memberOrder": "sequential",
      "members": [
        {
          "target": "raw-host",
          "weightFunction": "return 1"
        }
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y
  

Rule Language

Some blocks, such as the split and firstMatch types, have a rule field that contains a small function in a very simple programming language. This field is used to filter any incoming client requests in order to determine how to rule block should react.

In the case of a split block, the rule is evaluated and if it is true the client is sent to the onMatch part of the block, otherwise it is sent to the onMiss part for further evaluation.

In the case of a firstMatch block, the rule for each target will be evaluated top to bottom in order until either a rule evaluates to true or the list is exhausted. If a rule evaluates to true, the client will be sent to the onMatch part of the block, otherwise the next target in the list will be tried. If all targets have been exhausted, then the entire rule evaluation will fail, and the routing tree will be restarted with the firstMatch block effectively removed.

Example of Boolean Functions

Let’s say we have an ESB3024 Router set up with a session group that matches Apple devices (named “Apple”). To route all Apple devices to a specific streamer one would simply create a split block with the following rule:

in_session_group('Apple')

In order to make more complex rules it’s possible to combine several checks like this in the same rule. Let’s extend the hypothetical ESB3024 Router above with a configured subnet with all IP addresses in Europe (named “Europe”). To make a rule that accepts any clients using an Apple device and living outside of Europe, but only as long as the reported load on the streamer (as indicated by the selection input variable “europe_load_mbps”) is less than 1000 megabits per second one could make an offload block with the following rule (without linebreaks):

in_session_group('Apple')
    and not in_subnet('Europe')
    and lt('europe_load_mbps', 1000)

In this example in_session_group('Apple') will be true if the client belongs to the session group named ‘Apple’. The function call in_subnet('Europe') is true if the client’s IP belongs to the subnet named ‘Europe’, but the word not in front of it reverses the value so the entire section ends up being false if the client is in Europe. Finally lt('europe_load_mbps', 1000) is true if there is a selection input variable named “europe_load_mbps” and its value is less than 1000.

Since the three parts are conjoined with the and keyword they must all be true for the entire rule to match. If the keyword or had been used instead it would have been enough for any of the parts to be true for the rule to match.

Example of Numeric Functions

A hypothetical CDN has two streamers with different capacity; Host_1 has roughly twice the capacity of Host_2. A simple random load balancing would put undue stress on the second host since it will receive as much traffic as the more capable Host_1.

This can be solved by using a weighted random distribution rule block with suitable rules for the two hosts:

{
    "targets": [
        {
            "target": "Host_1",
            "condition": "always()",
            "weight": "100"
        }
        {
            "target": "Host_2",
            "condition": "always()",
            "weight": "50"
        },
    ]
}

resulting in Host_1 receiving twice as many requests as Host_2 as its weight function is double that of Host_2.

If the CDN is capable of reporting the free capacity of the hosts, for example by writing to a selection input variable for each host, it’s easy to write a more intelligent load balancing rule by making the weights correspond to the amount of capacity left on each host:

{
    "targets": [
        {
            "target": "Host_1",
            "condition": "always()",
            "weight": "si('free_capacity_host_1')"
        }
        {
            "target": "Host_2",
            "condition": "always()",
            "weight": "si('free_capacity_host_2')"
        },
    ]
}

It is also possible to write custom Lua functions that return suitable weights, perhaps taking the host as an argument:

{
    "targets": [
        {
            "target": "Host_1",
            "condition": "always()",
            "weight": "intelligent_weight_function('Host_1')"
        }
        {
            "target": "Host_2",
            "condition": "always()",
            "weight": "intelligent_weight_function('Host_1')"
        },
    ]
}

These different weight rules can of course be combined in the same rule block, with one target having a hard coded number, another using a dynamically updated selection input variable and yet another having a custom-built function.

Due to limitations in the random number generator used to distribute requests, it’s better to use somewhat large values, around 100–1000 or so, than to use small values near 0.

Built-in Functions

The following built-in functions are available when writing rules:

  • in_session_group(str name): True if session belongs to session group <name>
  • in_all_session_groups(str sg_name, ...): True if session belongs to all specified session groups
  • in_any_session_group(str sg_name, ...): True if session belongs to any specified session group
  • in_subnet(str subnet_name): True if client IP belongs to the named subnet
  • gt(str si_var, number value): True if selection_inputs[si_var] > value
  • gt(str si_var1, str si_var2): True if selection_inputs[si_var1] > selection_inputs[si_var2]
  • ge(str si_var, number value): True if selection_inputs[si_var] >= value
  • ge(str si_var1, str si_var2): True if selection_inputs[si_var1] >= selection_inputs[si_var2]
  • lt(str si_var, number value): True if selection_inputs[si_var] < value
  • lt(str si_var1, str si_var2): True if selection_inputs[si_var1] < selection_inputs[si_var2]
  • le(str si_var, number value): True if selection_inputs[si_var] <= value
  • le(str si_var1, str si_var2): True if selection_inputs[si_var1] <= selection_inputs[si_var2]
  • eq(str si_var, number value): True if selection_inputs[si_var] == value
  • eq(str si_var1, str si_var2): True if selection_inputs[si_var1] == selection_inputs[si_var2]
  • neq(str si_var, number value): True if selection_inputs[si_var] != value
  • neq(str si_var1, str si_var2): True if selection_inputs[si_var1] != selection_inputs[si_var2]
  • si(str si_var): Returns the value of selection_inputs[si_var] if it is defined and non-negative, otherwise it returns 0.
  • always(): Returns true, useful when creating weighted rule blocks.
  • never(): Returns false, opposite of always().

These functions, as well as custom functions written in Lua and uploaded to the ESB3024 Router, can be combined to make suitably precise rules.

Combining Multiple Boolean Functions

In order to make the rule language easy to work with, it is fairly restricted and simple. One restriction is that it’s only possible to chain multiple function results together using either and or or, but not a combination of both conjunctions.

Statements joined with and or or keywords are evaluated one by one, starting with the left-most statement and moving right. As soon as the end result of the entire expression is certain, the evaluation ends. This means that evaluation ends with the first false statement for and expressions since a single false component means the entire expression must also be false. It also means that evaluation ends with the first true statement for or expressions since only one component must be true for the entire statement to be true as well. This is known as short-circuit or lazy evaluation.

Custom Functions

It is possible to write extremely complex Lua functions that take many parameters or calculations into consideration when evaluating an incoming client request. By writing such functions and making sure that they return only non-negative integer values and uploading them to the router they can be used from the rule language. Simply call them like any of the built-in functions listed above, using strings and numbers as arguments if necessary, and their result will be used to determine the routing path to use.

Formal Syntax

The full syntax of the language can be described in just a few lines of BNF grammar:

<rule>               := <weight_rule> | <match_rule> | <value_rule>
<weight_rule>        := "if" <compound_predicate> "then" <weight> "else" <weight>
<match_rule>         := <compound_predicate>
<value_rule>         := <weight>
<compound_predicate> := <logical_predicate> |
                        <logical_predicate> ["and" <logical_predicate> ...] |
                        <logical_predicate> ["or" <logical_predicate> ...] |
<logical_predicate>  := ["not"] <predicate>
<predicate>          := <function_name> "(" ")" |
                        <function_name> "(" <argument> ["," <argument> ...] ")"
<function_name>      := <letter> [<function_name_tail> ...]
<function_name_tail> := empty | <letter> | <digit> | "_"
<argument>           := <string> | <number>
<weight>             := integer | <predicate>
<number>             := float | integer
<string>             := "'" [<letter> | <digit> | <symbol> ...] "'"

Building a Routing Configuration

This example sets up an entire routing configuration for a system with a ESB3008 Request Router, two streamers and the Apple devices outside of Europe example used earlier in this document. Any clients not matching the criteria will be sent to an offload CDN with two streamers in a simple uniformly randomized load balancing setup.

Set up Session Group

First make a classifier and a session group that uses it:

$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: userAgent
  Adding a 'userAgent' element
    classifier : {
      name (default: ): Apple
      type (default: userAgent): ⏎
      inverted (default: False): ⏎
      patternType (default: stringMatch): ⏎
      pattern (default: ): *apple*
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: ⏎
]
Generated config:
{
  "classifiers": [
    {
      "name": "Apple",
      "type": "userAgent",
      "inverted": false,
      "patternType": "stringMatch",
      "pattern": "*apple*"
    }
  ]
}
Merge and apply the config? [y/n]: y

$ confcli services.routing.sessionGroups -w
Running wizard for resource 'sessionGroups'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

sessionGroups : [
  sessionGroup : {
    name (default: ): Apple
    classifiers : [
      classifier (default: ): Apple
      Add another 'classifier' element to array 'classifiers'? [y/N]: ⏎
    ]
  }
  Add another 'sessionGroup' element to array 'sessionGroups'? [y/N]: ⏎
]
Generated config:
{
  "sessionGroups": [
    {
      "name": "Apple",
      "classifiers": [
        "Apple"
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y

Set up Hosts

Create two host groups and add a Request Router to the first and two streamers to the second, which will be used for offload:

$ confcli services.routing.hostGroups -w
Running wizard for resource 'hostGroups'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

hostGroups : [
  hostGroup can be one of
    1: dns
    2: host
    3: redirecting
  Choose element index or name: redirecting
  Adding a 'redirecting' element
    hostGroup : {
      name (default: ): internal
      type (default: redirecting): ⏎
      httpPort (default: 80): ⏎
      httpsPort (default: 443): ⏎
      hosts : [
        host : {
          name (default: ): rr1
          hostname (default: ): rr1.example.com
          ipv6_address (default: ): ⏎
        }
        Add another 'host' element to array 'hosts'? [y/N]: ⏎
      ]
    }
  Add another 'hostGroup' element to array 'hostGroups'? [y/N]: y
  hostGroup can be one of
    1: dns
    2: host
    3: redirecting
  Choose element index or name: host
  Adding a 'host' element
    hostGroup : {
      name (default: ): external
      type (default: host): ⏎
      httpPort (default: 80): ⏎
      httpsPort (default: 443): ⏎
      hosts : [
        host : {
          name (default: ): offload-streamer1
          hostname (default: ): streamer1.example.com
          ipv6_address (default: ): ⏎
        }
        Add another 'host' element to array 'hosts'? [y/N]: y
        host : {
          name (default: ): offload-streamer2
          hostname (default: ): streamer2.example.com
          ipv6_address (default: ): ⏎
        }
        Add another 'host' element to array 'hosts'? [y/N]: ⏎
      ]
    }
  Add another 'hostGroup' element to array 'hostGroups'? [y/N]: ⏎
]
Generated config:
{
  "hostGroups": [
    {
      "name": "internal",
      "type": "redirecting",
      "httpPort": 80,
      "httpsPort": 443,
      "hosts": [
        {
          "name": "rr1",
          "hostname": "rr1.example.com",
          "ipv6_address": ""
        }
      ]
    },
    {
      "name": "external",
      "type": "host",
      "httpPort": 80,
      "httpsPort": 443,
      "hosts": [
        {
          "name": "offload-streamer1",
          "hostname": "streamer1.example.com",
          "ipv6_address": ""
        },
        {
          "name": "offload-streamer2",
          "hostname": "streamer2.example.com",
          "ipv6_address": ""
        }
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y

Create Load Balancing and Offload Block

Add both offload streamers as targets in a randomgroup block:

$ confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: random
  Adding a 'random' element
    rule : {
      name (default: ): balancer
      type (default: random): ⏎
      targets : [
        target (default: ): offload-streamer1
        Add another 'target' element to array 'targets'? [y/N]: y
        target (default: ): offload-streamer2
        Add another 'target' element to array 'targets'? [y/N]: ⏎
      ]
    }
  Add another 'rule' element to array 'rules'? [y/N]: ⏎
]
Generated config:
{
  "rules": [
    {
      "name": "balancer",
      "type": "random",
      "targets": [
        "offload-streamer1",
        "offload-streamer2"
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y

Then create a split block with the request router and the load balanced CDN as targets:

$ confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: split
  Adding a 'split' element
    rule : {
      name (default: ): offload
      type (default: split): ⏎
      rule (default: ): in_session_group('Apple') and not in_subnet('Europe') and lt('europe_load_mbps', 1000)
      onMatch (default: ): rr1
      onMiss (default: ): balancer
    }
  Add another 'rule' element to array 'rules'? [y/N]: ⏎
]
Generated config:
{
  "rules": [
    {
      "name": "offload",
      "type": "split",
      "condition": "in_session_group('Apple') and not in_subnet('Europe') and lt('europe_load_mbps', 1000)",
      "onMatch": "rr1",
      "onMiss": "balancer"
    }
  ]
}
Merge and apply the config? [y/n]: y

The last step required is to set the entrypoint of the routing tree so the router knows where to start evaluating:

$ confcli services.routing.entrypoint offload
services.routing.entrypoint = 'offload'

Evaluate

Now that all the rules have been set up properly and the router has been reconfigured. The translated configuration can be read from the router’s configuration API:

$ curl -k https://router-host:5001/v2/configuration  2> /dev/null | jq .routing
{
  "id": "offload",
  "member_order": "sequential",
  "members": [
    {
      "host_id": "rr1",
      "id": "offload.rr1",
      "weight_function": "return ((in_session_group('Apple') ~= 0) and
                          (in_subnet('Europe') == 0) and
                          (lt('europe_load_mbps', 1000) ~= 0) and 1) or 0 "
    },
    {
      "id": "offload.balancer",
      "member_order": "weighted",
      "members": [
        {
          "host_id": "offload-streamer1",
          "id": "offload.balancer.offload-streamer1",
          "weight_function": "return 100"
        },
        {
          "host_id": "offload-streamer2",
          "id": "offload.balancer.offload-streamer2",
          "weight_function": "return 100"
        }
      ],
      "weight_function": "return 1"
    }
  ],
  "weight_function": "return 100"
}

Note that the configuration language code has been translated into its Lua equivalent.

1.5.3 - Session Groups and Classification

How to classify clients into session groups and use them in routing

ESB3024 Router provides a flexible classification engine, allowing the assignment of clients into session groups that can then be used to base routing decisions on.

Session Classification

In order to perform routing it is necessary to classify incoming sessions according to the relevant parameters. This is done through session groups and their associated classifiers.

There are different ways of classifying a request:

  • Strings with wildcards: Simple case-insensitive string pattern with support for adding asterisks (’*’) in order to match any value at that point in the pattern.
  • String with regular expressions: A complex string matching pattern capable of matching more complicated strings than the simple wildcard matching type.

Valid string matching sources are content_url_path, content_url_query_parameters, hostname and user_agent, examples of which will be shown below.

  • GeoIP: Based on the geographic location of the client, supporting wildcard matching. Geographic location data is provided by MaxMind. The possible values to match with are any combinations of:
    • Continent
    • Country
    • Cities
    • ASN
  • Anonymous IP: Classifies clients using an anonymous IP. Database of anonymous IPs is provided by MaxMind.
  • IP range: Based on whether a client’s IP belongs to any of the listed IP ranges or not.
  • Subnet: Tests if a client’s IP belongs to a named subnet, see Subnets for more details.
  • ASN ID list: Checks to see if a client’s IP belongs to any of the specified ASN IDs.
  • Random: Randomly classifies client according to a given probability.

A session group may have more than one classifier. If it does, all the classifiers must match the incoming client request for it to belong to the session group. It is also possible for a request to belong to multiple session groups, or to none.

To send certain clients to a specific host you first need to create a suitable classifier using confcli in wizard mode. The wizard will guide you through the process of creating a new entry, asking you what value to input for each field and helping you by telling you what inputs are allowed for restricted fields such as the string comparison source mentioned above:

$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: geoip
  Adding a 'geoip' element
    classifier : {
      name (default: ): sweden_matcher
      type (default: geoip): ⏎
      inverted (default: False): ⏎
      continent (default: ): ⏎
      country (default: ): sweden
      cities : [
        city (default: ): ⏎
        Add another 'city' element to array 'cities'? [y/N]: ⏎
      ]
      asn (default: ): ⏎
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: ⏎
]
Generated config:
{
  "classifiers": [
    {
      "name": "sweden_matcher",
      "type": "geoip",
      "inverted": false,
      "continent": "",
      "country": "sweden",
      "cities": [
        ""
      ],
      "asn": ""
    }
  ]
}
Merge and apply the config? [y/n]: y
$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: ipranges
  Adding a 'ipranges' element
    classifier : {
      name (default: ): company_matcher
      type (default: ipranges): ⏎
      inverted (default: False): ⏎
      ipranges : [
        iprange (default: ): 90.128.0.0/12
        Add another 'iprange' element to array 'ipranges'? [y/N]: ⏎
      ]
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: ⏎
]
Generated config:
{
  "classifiers": [
    {
      "name": "company_matcher",
      "type": "ipranges",
      "inverted": false,
      "ipranges": [
        "90.128.0.0/12"
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: stringMatcher
  Adding a 'stringMatcher' element
    classifier : {
      name (default: ): apple_matcher
      type (default: stringMatcher): ⏎
      inverted (default: False): ⏎
      source (default: content_url_path): user_agent
      pattern (default: ): *apple*
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: ⏎
]
Generated config:
{
  "classifiers": [
    {
      "name": "apple_matcher",
      "type": "stringMatcher",
      "inverted": false,
      "source": "user_agent",
      "pattern": "*apple*"
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: regexMatcher
  Adding a 'regexMatcher' element
    classifier : {
      name (default: ): content_matcher
      type (default: regexMatcher): ⏎
      inverted (default: False): ⏎
      source (default: content_url_path): ⏎
      pattern (default: ): .*/(live|news_channel)/.*m3u8
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: ⏎
]
Generated config:
{
  "classifiers": [
    {
      "name": "content_matcher",
      "type": "regexMatcher",
      "inverted": false,
      "source": "content_url_path",
      "pattern": ".*/(live|news_channel)/.*m3u8"
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: subnet
  Adding a 'subnet' element
    classifier : {
      name (default: ): company_matcher
      type (default: subnet): ⏎
      inverted (default: False): ⏎
      pattern (default: ): company
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: ⏎
]
Generated config:
{
  "classifiers": [
    {
      "name": "company_matcher",
      "type": "subnet",
      "inverted": false,
      "pattern": "company"
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: hostName
  Adding a 'hostName' element
    classifier : {
      name (default: ): host_name_classifier
      type (default: hostName): ⏎
      inverted (default: False): ⏎
      patternType (default: stringMatch): ⏎
      pattern (default: ): *live.example*
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: n
]
Generated config:
{
  "classifiers": [
    {
      "name": "host_name_classifier",
      "type": "hostName",
      "inverted": false,
      "patternType": "stringMatch",
      "pattern": "*live.example*"
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: contentUrlPath
  Adding a 'contentUrlPath' element
    classifier : {
      name (default: ): vod_matcher
      type (default: contentUrlPath): ⏎
      inverted (default: False): ⏎
      patternType (default: stringMatch): ⏎
      pattern (default: ): *vod*
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: n
]
Generated config:
{
  "classifiers": [
    {
      "name": "vod_matcher",
      "type": "contentUrlPath",
      "inverted": false,
      "patternType": "stringMatch",
      "pattern": "*vod*"
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: contentUrlQueryParameters
  Adding a 'contentUrlQueryParameters' element
    classifier : {
      name (default: ): bitrate_matcher
      type (default: contentUrlQueryParameters): ⏎
      inverted (default: False): ⏎
      patternType (default: stringMatch): regex
      pattern (default: ): .*bitrate=100000.*
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: n
]
Generated config:
{
  "classifiers": [
    {
      "name": "bitrate_matcher",
      "type": "contentUrlQueryParameters",
      "inverted": false,
      "patternType": "regex",
      "pattern": ".*bitrate=100000.*"
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: userAgent
  Adding a 'userAgent' element
    classifier : {
      name (default: ): iphone_matcher
      type (default: userAgent): ⏎
      inverted (default: False): ⏎
      patternType (default: stringMatch): regex
      pattern (default: ): i(P|p)hone
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: n
]
Generated config:
{
  "classifiers": [
    {
      "name": "iphone_matcher",
      "type": "userAgent",
      "inverted": false,
      "patternType": "regex",
      "pattern": "i(P|p)hone"
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: asnIds
  Adding a 'asnIds' element
    classifier : {
      name (default: ): asn_matcher
      type (default: asnIds): ⏎
      inverted (default: False): ⏎
      asnIds <The list of ASN IDs to accept. (default: [])>: [
        asnId: 1
        Add another 'asnId' element to array 'asnIds'? [y/N]: y
        asnId: 2
        Add another 'asnId' element to array 'asnIds'? [y/N]: y
        asnId: 3
        Add another 'asnId' element to array 'asnIds'? [y/N]: ⏎
      ]
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: ⏎
]
Generated config:
{
  "classifiers": [
    {
      "name": "asn_matcher",
      "type": "asnIds",
      "inverted": false,
      "asnIds": [
        1,
        2,
        3
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: random
  Adding a 'random' element
    classifier <A classifier randomly applying to clients based on the provided probability. (default: OrderedDict())>: {
      name (default: ): random_matcher
      type (default: random):
      probability (default: 0.5): 0.7
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: n
]
Generated config:
{
  "classifiers": [
    {
      "name": "random_matcher",
      "type": "random",
      "probability": 0.7
    }
  ]
}
Merge and apply the config? [y/n]: y
  
$ confcli services.routing.classifiers -w
Running wizard for resource 'classifiers'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

classifiers : [
  classifier can be one of
    1: anonymousIp
    2: asnIds
    3: contentUrlPath
    4: contentUrlQueryParameters
    5: geoip
    6: hostName
    7: ipranges
    8: random
    9: regexMatcher
    10: stringMatcher
    11: subnet
    12: userAgent
  Choose element index or name: anonymousIp
  Adding a 'anonymousIp' element
    classifier : {
      name (default: ): anon_ip_matcher
      type (default: anonymousIp):
      inverted (default: False):
    }
  Add another 'classifier' element to array 'classifiers'? [y/N]: n
]
Generated config:
{
  "classifiers": [
    {
      "name": "anon_ip_matcher",
      "type": "anonymousIp",
      "inverted": false
    }
  ]
}
Merge and apply the config? [y/n]: y
  

These classifiers can now be used to construct session groups and properly classify clients. Using the examples above, let’s create a session group classifying clients from Sweden using an Apple device:

$ confcli services.routing.sessionGroups -w
Running wizard for resource 'sessionGroups'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

sessionGroups : [
  sessionGroup : {
    name (default: ): inSwedenUsingAppleDevice
    classifiers : [
      classifier (default: ): sweden_matcher
      Add another 'classifier' element to array 'classifiers'? [y/N]: y
      classifier (default: ): apple_matcher
      Add another 'classifier' element to array 'classifiers'? [y/N]: ⏎
    ]
  }
  Add another 'sessionGroup' element to array 'sessionGroups'? [y/N]: ⏎
]
Generated config:
{
  "sessionGroups": [
    {
      "name": "inSwedenUsingAppleDevice",
      "classifiers": [
        "sweden_matcher",
        "apple_matcher"
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y

Clients classified by the sweden_matcher and apple_matcher classifiers will now be put in the session group inSwedenUsingAppleDevice. Using session groups in routing will be demonstrated later in this document.

Advanced Classification

The above example will simply apply all classifiers in the list, and as long as they all evaluate to true for a session, that session will be tagged with the session group. For situations where this isn’t enough, classifiers can instead be combined using simple logic statements to form complex rules.

A first simple example can be a session group that accepts any viewers in either ASN 1, 2 or 3 (corresponding to the classifier asn_matcher or living in Sweden. This can be done by creating a session group, and adding the following logic statement:

'sweden_matcher' OR 'asn_matcher'

A slightly more advanced case is where a session group should only contain sessions neither in any of the three ASNs nor in Sweden. This is done by negating the previous example:

NOT ('sweden_matcher' OR 'asn_matcher')

A single classifier can also be negated, rather than the whole statement, for example to accept any Swedish viewers except those in the three ASNs:

'sweden_matcher' AND NOT 'asn_matcher'

Arbitrarily complex statements can be created using classifier names, parentheses, and the keywords AND, OR and NOT.

For example a session group accepting any Swedish viewers except those in the Stockholm region unless they are also Apple users:

'sweden_matcher' AND (NOT 'stockholm_matcher' OR 'apple_matcher')

Note that the classifier names must be enclosed in single quotes when using this syntax.

Applying this kind of complex classifier using confcli is no more difficult than adding a single classifier at a time:

$ confcli services.routing.sessionGroups. -w
Running wizard for resource 'sessionGroups'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

sessionGroups : [
  sessionGroup : {
    name (default: ): complex_group
    classifiers : [
      classifier (default: ): 'sweden_matcher' AND (NOT 'stockholm_matcher' OR 'apple_matcher')
      Add another 'classifier' element to array 'classifiers'? [y/N]: ⏎
    ]
  }
  Add another 'sessionGroup' element to array 'sessionGroups'? [y/N]: ⏎
]
Generated config:
{
  "sessionGroups": [
    {
      "name": "complex_group",
      "classifiers": [
        "'sweden_matcher' AND (NOT 'stockholm_matcher' OR 'apple_matcher')"
      ]
    }
  ]
}
Merge and apply the config? [y/n]: y
  

1.5.4 - Advanced features

Detailed descriptions and examples of advanced features within ESB3024

1.5.4.1 - Content popularity

How to tune content popularity parameters and use it in routing

ESB3024 Router allows routing decisions based on content popularity. All incoming content requests are tracked to continuously update a content popularity ranking list. The popularity ranking algorithm is designed to let popular content quickly rise to the top while unpopular content decays and sinks towards the bottom.

Configuration

All configuration parameters for content popularity reside in the settings object of the configuration, an example of which can be seen below:

{
  "settings": {
    "content_popularity": {
      "algorithm": "scored_based",
      "session_group_names": ["vod_only"],
      "score_based:": {
        "requests_between_popularity_decay": 1000,
        "popularity_list_max_size": 100000,
        "popularity_prediction_factor": 2.5,
        "popularity_decay_fraction": 0.2
      },
      "time_based": {
        "intervals_per_hour": 10
      }
    }
  }
}

The field algorithm dictates which content popularity tracking algorithm to use, can either be score_based or time_based.

The field session_group_names defines the sessions for which content popularity should be tracked. In the example above, session belonging to the vod_only session group will be tracked for content popularity. If left empty, content popularity will be tracked for all sessions.

The remaining configuration parameters are algorithm specific.

Score based algorithm

The field popularity_list_max_size defines the maximum amount of unique contents to track for popularity. This can be used to limit memory growth. A single entry in the popularity ranking list will at most consume 180 B of memory, giving an upper bound memory growth of \(180n_{\text{requests}}\) bytes. E.g. using "popularity_list_max_size": 1000 would consume at most 180⋅1,000 = 180,000 B = 0.18 MB. If the content popularity list is full, a request to unique content would replace the least popular content.

Setting a very high max size won’t impact performance, it will only consume more memory.

The field requests_between_popularity_decay defines the number of requests between each popularity decay update, an integral component of this feature.

The fields popularity_prediction_factor and popularity_decay_fraction tune the behaviour of the content popularity ranking algorithm, explained further below.

Decay update

To allow for popular content to quickly rise in popularity and unpopular content to sink, a dynamic popularity ranking algorithm is used. The goal of the algorithm is to track content popularity in real time, allowing routing decisions based on the requested content’s popularity. The algorithm is applied every decay update.

The algorithm uses current trending content to predict content popularity. The field popularity_prediction_factor regulates how much the algorithm should rely on predicted popularity. A high prediction factor allows rising content to quickly rise to high popularity but can also cause unpopular content with a sudden burst of requests to wrongfully rise to the top. A low prediction factor can cause stagnation in the popularity ranking, not allowing new popular content to rise to the top.

Unpopular content decays in popularity, the magnitude of which is regulated by popularity_decay_fraction. A high value will aggressively decay content popularity every decay update while a low value will bloat the ranking, causing stagnation. Once content decays to a trivially low popularity score, it is pruned from the content popularity list.

When configuring these tuning parameters, the most crucial data to consider is the size of your asset catalog, i.e. the number of unique contents you offer. The recommended values, obtained through testing, are presented in the table below. Note that the field popularity_prediction_factor is the principal factor in controlling the algorithm’s behaviour.

Catalog size \(n\)popularity_prediction_factorpopularity_decay_fraction
\(n\) < 10002.20.2
1000 < \(n\) < 50002.30.2
5000 < \(n\) < 100002.50.2
\(n\) > 100002.60.2

Time based algorithm

The time based algorithm only requires the configuration parameter intervals_per_hour. E.g., the value "intervals_per_hour": 10 would give 10 six minute intervals per hour. During each interval, all unique content requests has an associated counter, increasing by one for each incoming request. After an hour, all intervals have been cycled through. The counters in the first interval will be reset and all incoming content requests will increase the counters in the first interval again. This cycle continues forever.

When determining a single content’s popularity, the sum of each content’s counter in all intervals is used to determine a popularity ranking.

Usage in routing

Content popularity ranking is available in Lua through the simple member session.content_global_popularity, returning the requested content’s popularity ranking. E.g., the routing configuration below will route all requests to content with a popularity ranking lower than 10, i.e. top 10 most popular content, to the host edge-streamer while requests to content outside of the top 10 most popular will be routed to the host offload.

"routing": {
  "id": "routing_table",
  "member_order": "sequential",
  "members": [
    {
      "id": "edge",
      "weight_function": "return session.content_global_popularity < 11 and 1 or 0",
      "host_id": "edge-streamer"
    },
    {
      "id": "offload",
      "weight_function": "return 1",
      "host_id": "offload"
    }
  ]
}

1.5.4.2 - Consistent Hashing

Details and configuration considerations for using consistent hashing based routing

Consistent hashing based routing is a feature that can be used to distribute requests to a set of hosts in a cache friendly manner. By using Agile Content’s consistent distributed hash algorithm, the amount of cache redistribution is minimized within a set of hosts. Requests for a content will always be routed to the same set of hosts, the amount of which is configured by the spread factor, allowing high cache usage. When adding or removing hosts, the algorithm minimizes cache redistribution.

Say you have the host group [s1, s2, s3, s4, s5] and have configured spreadFactor = 3. A request for a content asset1 would then be routed to the same three hosts with one of them being selected randomly for each request. Requests for a different content asset2 would also be routed to one of three different hosts, most likely a different combination of hosts than requests for content asset1.

Example routing results with spreadFactor = 3:

  • Request for asset1 → route to one of [s1, s3, s4].
  • Request for asset2 → route to one of [s2, s4, s5].
  • Request for asset3 → route to one of [s1, s2, s5].

Since consistent hashing based routing ensures that requests for a specific content always get routed to the same set of hosts, the risk of cache misses are lowered on the hosts since they will be served the same content requests over and over again.

Note that the maximum value of spreadFactor is 64. Consequently, the highest amount of hosts you can use in a consistentHashing rule block is 64.

Three different hashing algorithms are available: MD5, SDBM and Murmur. The algorithm is chosen during configuration.

Configuration

Configuring consistent hashing based routing is easily done using confcli. Let’s configure the example described above:

confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: consistentHashing
  Adding a 'consistentHashing' element
    rule : {
      name (default: ): consistentHashingRule 
      type (default: consistentHashing): 
      spreadFactor (default: 1): 3
      hashAlgorithm (default: MD5):
      targets : [
        target : {
          target (default: ): s1
          enabled (default: True): 
        }
        Add another 'target' element to array 'targets'? [y/N]: y
        target : {
          target (default: ): s2
          enabled (default: True): 
        }
        Add another 'target' element to array 'targets'? [y/N]: y
        target : {
          target (default: ): s3
          enabled (default: True): 
        }
        Add another 'target' element to array 'targets'? [y/N]: y
        target : {
          target (default: ): s4
          enabled (default: True): 
        }
        Add another 'target' element to array 'targets'? [y/N]: y
        target : {
          target (default: ): s5
          enabled (default: True): 
        }
        Add another 'target' element to array 'targets'? [y/N]: n
      ]
    }
  Add another 'rule' element to array 'rules'? [y/N]: n
]
Generated config:
{
  "rules": [
    {
      "name": "consistentHashingRule",
      "type": "consistentHashing",
      "spreadFactor": 3,
      "hashAlgorithm": "MD5",
      "targets": [
        {
          "target": "s1",
          "enabled": true
        },
        {
          "target": "s2",
          "enabled": true
        },
        {
          "target": "s3",
          "enabled": true
        },
        {
          "target": "s4",
          "enabled": true
        },
        {
          "target": "s5",
          "enabled": true
        }
      ]
    }
  ]
}

Adding hosts

Adding a host to the list will give an additional target for the consistent hashing algorithm to route requests to. This will shift content distribution onto the new host.

confcli services.routing.rules.consistentHashingRule.targets -w
Running wizard for resource 'targets'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

targets : [
  target : {
    target (default: ): s6
    enabled (default: True): 
  }
  Add another 'target' element to array 'targets'? [y/N]: n
]
Generated config:
{
  "targets": [
    {
      "target": "s6",
      "enabled": true
    }
  ]
}
Merge and apply the config? [y/n]: y

Removing hosts

There is one very important caveat of using a consistent hashing rule block. As long as you don’t modify the list of hosts, the consistent hashing algorithm will keep routing requests to the same hosts. However, if you remove a host from the block in any position except the last, the consistent hashing algorithm’s behaviour will change and the algorithm cannot maintain a minimum amount of cache redistribution.

If you’re in a situation where you have to remove a host from the routing targets but want to keep the same consistent hashing behaviour, e.g. during very high load, you’ll have to toggle that target’s enabled field to false. E.g., disabling requests to s2 can be accomplished by:

$ confcli services.routing.rules.consistentHashingRule.targets.1.enabled false
services.routing.rules.consistentHashingRule.targets.1.enabled = False
$ confcli services.routing.rules.consistentHashingRule.targets.1
{
    "1": {
        "target": "s2",
        "enabled": false
    }
}

If you modify the list order or remove hosts, it is highly recommended to do so during moments where a higher rate of cache misses are acceptable.

1.5.4.3 - Predictive load balancing

Configuring predictive load balancing in ESB3024 Router

Why use predictive load balancing?

Predictive load balancing is a tool that can be used to avoid overloading hosts with traffic. Consider the case where a popular event starts at a certain time, let’s say 12 PM. A spike in traffic will be routed to the hosts that are streaming the content at 12 PM, most of them starting at low bitrates. A host might have sufficient bandwidth left to take on more clients but when the recently connected clients start ramping up in video quality and increase their bitrate, the host can quickly become overloaded, possibly dropping incoming requests or going offline. Predictive load balancing solves this issue by considering how many times a host recently been redirected to.

Basic configuration

The router allows predicting incoming load for individual hosts. Through the use of the selection input API, the routing engine can predict incoming load by tracking recent host selections and make routing decisions accordingly.

What is considered recent is configurable and defaults to 500 milliseconds:

$ confcli services.routing.tuning.target.recentDurationMilliseconds
{
    "recentDurationMilliseconds": 500
}
$ confcli services.routing.tuning.target.recentDurationMilliseconds 1000
services.routing.tuning.target.recentDurationMilliseconds = 1000
{
  "tuning": {
    "target_recent_duration_milliseconds": 500
  }
}

How to use predictive load balancing

The standard Lua library provides four functions for predictive load balancing that can be used when constructing conditions/weight functions: host_bitrate() , host_bitrate_custom(), host_has_bw() and host_has_bw_custom(). All require data to be supplied to the selection input API and apply only to leaf nodes in the routing tree. In order for predictive load balancing to work properly the data must be updated at regular intervals. The data needs to be supplied by the target system.

These functions are suitable to used as host health checks. To configure host health checks, see configuring CDNs and hosts.

Note that host_bitrate() and host_has_bw() rely on data supplied by metrics agents, detailed in Cache hardware metrics: monitoring and routing.

host_bitrate_custom() and host_has_bw_custom() rely on manually supplied selection input data, detailed in selection input API. The bitrate unit depends on the data submitted to the selection input API.

host_bitrate()

host_bitrate() returns the predicted bitrate (in megabits per second) of the host after the recently connected clients start ramping up in streaming quality. The function accepts up to four arguments:

  • interface: The name of the interface to use for bitrate prediction.
  • Optional avg_bitrate: the average bitrate per client, defaults to 6 megabits per second.
  • Optional num_routers: the number of routers that can route to this host, defaults to 1. This is important to accurately predict the incoming load if multiple routers are used.
  • Optional host: The name of the host to use for bitrate prediction. Defaults to the current host if not provided.

Examples of usage:

host_bitrate({interface="eths0"})
host_bitrate({avg_bitrate=1, interface="eths0"})
host_bitrate({num_routers=2, interface="eths0"})
host_bitrate({avg_bitrate=1, num_routers=4, interface="eths0"})
host_bitrate({avg_bitrate=1, num_routers=4, host="custom_host", interface="eths0"})

host_bitrate() calculates the predicted bitrate as:

predicted_host_bitrate = current_host_bitrate + (recent_connections * avg_bitrate * num_routers)

host_bitrate_custom()

Same functionality as host_bitrate() but uses a custom selection input variable as bitrate input instead of accessing hardware metrics. The function accepts up to three arguments:

  • custom_bitrate_var: The name of the selection input variable to be used for accessing current host bitrate.
  • Optional avg_bitrate: see host_bitrate() documentation above.
  • Optional num_routers: see host_bitrate() documentation above.
host_bitrate_custom({custom_bitrate_var="host1_current_bitrate"})
host_bitrate_custom({avg_bitrate=1, custom_bitrate_var="host1_current_bitrate"})
host_bitrate_custom({num_routers=4, custom_bitrate_var="host1_current_bitrate"})

host_has_bw()

Instead of accessing the predicted bitrate of a host through host_bitrate(), host_has_bw() returns 1 if the host is predicted to have enough bandwidth left to take on more clients after recent connections ramp up in bitrate, otherwise it returns 0. The function accepts up to five arguments:

  • interface: see host_bitrate() documentation above.
  • Optional avg_bitrate: see host_bitrate() documentation above.
  • Optional num_routers: see host_bitrate() documentation above.
  • Optional host: see host_bitrate() documentation above.
  • Optional margin: the bitrate (megabits per second) headroom that should be taken into account during calculation, defaults to 0.

host_has_bw() returns whether or not the following statement is true:

predicted_host_bitrate + margin < host_bitrate_capacity

Examples of usage:

host_has_bw({interface="eths0"})
host_has_bw({margin=10, interface="eth0"})
host_has_bw({avg_bitrate=1, interface="eth0"})
host_has_bw({num_routers=4, interface="eth0"})
host_has_bw({host="custom_host", interface="eth0"})

host_has_bw_custom()

Same functionality as host_has_bw() but uses a custom selection input variable as bitrate and capacity input. The function accepts up to five arguments:

  • custom_capacity_var: the name of the selection input variable to be used for accessing host capacity.
  • custom_bitrate_var: see host_bitrate_custom() documentation
  • Optional margin: see host_has_bw() documentation above. above.
  • Optional avg_bitrate: see host_bitrate() documentation above.
  • Optional num_routers: see host_bitrate() documentation above.

Examples of usage:

host_has_bw_custom({custom_capacity_var="host1_capacity", custom_bitrate_var="host1_current_bitrate"})
host_has_bw_custom({margin=10, custom_capacity_var="host1_capacity", custom_bitrate_var="host1_current_bitrate"})
host_has_bw_custom({avg_bitrate=1, custom_capacity_var="host1_capacity", custom_bitrate_var="host1_current_bitrate"})
host_has_bw_custom({num_routers=4, custom_capacity_var="host1_capacity", custom_bitrate_var="host1_current_bitrate"})

Examples in routing

When using confcli it’s not recommended to use host_bitrate() since it’s not possible to make comparisons using <, > or similar operators. Using host_has_bw() makes it easy to construct conditions utilizing predictive load balancing.

host_has_bw() and host_has_bw_custom() are excellent candidates to be used as health check functions for hosts, see configuring CDNs and hosts for more details.

$ confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: weighted
  Adding a 'weighted' element
    rule : {
      name (default: ): weighted_and_has_bw
      type (default: weighted):
      targets : [
        target : {
          target (default: ): host1
          weight (default: 100):
          condition (default: always()): host_has_bw({interface="eths0"})
        }
        Add another 'target' element to array 'targets'? [y/N]: y
        target : {
          target (default: ): host2
          weight (default: 100): 100
          condition (default: always()): host_has_bw({margin=1000, interface="eths0"})
        }
        Add another 'target' element to array 'targets'? [y/N]: y
        target : {
          target (default: ): host3
          weight (default: 100):
          condition (default: always()): host_has_bw({avg_bitrate=1, num_routers=2, margin=5000, interface="eths0"})
        }
        Add another 'target' element to array 'targets'? [y/N]: n
      ]
    }
  Add another 'rule' element to array 'rules'? [y/N]: n
]
Generated config:
{
  "rules": [
    {
      "name": "weighted_and_has_bw",
      "type": "weighted",
      "targets": [
        {
          "target": "host1",
          "weight": "100",
          "condition": "host_has_bw({interface="eths0"})"
        },
        {
          "target": "host2",
          "weight": "100",
          "condition": "host_has_bw({margin=1000, interface="eths0"})"
        },
        {
          "target": "host3",
          "weight": "100",
          "condition": "host_has_bw({avg_bitrate=1, num_routers=2, margin=5000, interface="eths0"})"
        }
      ]
    }
  ]
}
"routing": {
  "id": "weighted_and_has_bw",
  "member_order": "sorted",
  "members": [
    {
      "id": "1",
      "host_id": "host1",
      "weight_function": "return host_bitrate({interface="eths0"}) > 0 and 1 or 0"
    },
    {
      "id": "2",
      "host_id": "host2",
      "weight_function": "return host_bitrate({avg_bitrate=1, interface="eths0"}) > 10000 and 1 or 0"
    },
    {
      "id": "3",
      "host_id": "host3",
      "weight_function": "return host_has_bw({avg_bitrate=1, num_routers=2, margin=5000, interface="eths0"}) and 1 or 0"
    }
  ],
  "weight_function": "return 1"
}

1.5.4.4 - Security token verification

Only allow requests that contain a correct security token

The security token verification feature allows for ESB3024 Router to only process requests that contain a correct security token. The token is generated by the client, for example in the portal, using an algorithm that it shares with the router. The router verifies the token and rejects the request if the token is incorrect.

It is beyond the scope of this document to describe how the token is generated, that is described in the Security Tokens application note that is installed with the ESB3024 Router’s extra documentation.

Setting up a routing rule

The token verification is performed by calling the verify_security_token() function from a routing rule. The function returns 1 if the token is correct, otherwise it returns 0. It should typically be called from the first routing rule, to make requests with bad tokens fail as early as possible.

The confcli example assumes that the router already has rules configured, with an entry point named select_cdn. Token verification is enabled by inserting an “allow” rule first in the rule list.

confcli services.routing.rules -w
Running wizard for resource 'rules'

Hint: Hitting return will set a value to its default.
Enter '?' to receive the help string

rules : [
  rule can be one of
    1: allow
    2: consistentHashing
    3: contentPopularity
    4: deny
    5: firstMatch
    6: random
    7: rawGroup
    8: rawHost
    9: split
    10: weighted
  Choose element index or name: allow
  Adding a 'allow' element
    rule : {
      name (default: ): token_verification
      type (default: allow):
      condition (default: always()): verify_security_token()
      onMatch (default: ): select_cdn
    }
  Add another 'rule' element to array 'rules'? [y/N]: n
]
Generated config:
{
  "rules": [
    {
      "name": "token_verification",
      "type": "allow",
      "condition": "verify_security_token()",
      "onMatch": "select_cdn"
    }
  ]
}
Merge and apply the config? [y/n]: y

$ confcli services.routing.entrypoint token_verification
services.routing.entrypoint = 'token_verification'
"routing": {
  "id": "token_verification",
  "member_order": "sequential",
  "members": [
    {
      "id": "token_verification.0.select_cdn",
      "member_order": "weighted",
      "members": [
        ...
      ],
      "weight_function": "return verify_security_token() ~= 0"
    },
    {
      "id": "token_verification.1.rejected",
      "member_order": "sequential",
      "members": [],
      "weight_function": "return 1"
    }
  ],
  "weight_function": "return 100"
},

Configuring security token options

The secret parameter is not part of the router request, but needs to be configured separately in the router. That can be done with the host-config tool that is installed with the router.

Besides configuring the secret, host-config can also configure floating sessions and a URL prefix. Floating sessions are sessions that are not tied to a specific IP address. When that is enabled, the token verification will not take the IP address into account when verifying the token.

The security token verification is configured per host, where a host is the name of the host that the request was sent to. This makes it possible for a router to support multiple customer accounts, each with their own secret. If no configuration is found for a host, a configuration with the name default is used.

host-config supports three commands: print, set and delete.

Print

The print command prints the current configuration for a host. The following parameters are supported:

host-config print [-n <host-name>]

By default it prints the configuration for all hosts, but if the optional -n flag is given it will print the configuration for a single host.

Set

The set command sets the configuration for a host. The configuration is given as command line parameters. The following parameters are supported:

host-config set
    -n <host-name>
    [-f floating]
    [-p url-prefix]
    [-r <secret-to-remove>]
    [-s <secret-to-add>]
  • -n <host-name> - The name of the host to configure.
  • -f floating - A boolean option that specifies if floating sessions are accepted. The parameter accepts the values true and false.
  • -p url-prefix - A URL prefix that is used for identifying requests that come from a certain account. This is not used when verifying tokens.
  • -r <secret-to-remove> - A secret that should be removed from the list of secrets.
  • -s <secret-to-add> - A secret that should be added to the list of secrets.

For example, to set the secret “secret-1” and enable floating sessions for the default host, the following command can be used:

host-config set -n default -s secret-1 -f true

The set command only touches the configuration options that are mentioned on the command line, so the following command line will add a second secret to the default host without changing the floating session setting:

host-config set -n default -s secret-2

It is possible to set multiple secrets per host. This is useful when updating a secret, then both the old and the new secret can be valid during the transition period. After the transition period the old secret can be removed by typing:

host-config set -n default -r secret-1

Delete

The delete command deletes the configuration for a host. It supports the following parameters:

host-config delete -n <host-name>

For example, to delete the configuration for example.com, the following command can be used:

host-config delete -n example.com

Global options

host-config also has a few global options. They are:

  • -k <security-key> - The security key that is used when communicating with the router. This is normally retrieved automatically.
  • -h - Print a help message and exit.
  • -r <router> - The router to connect to. This default to localhost, but can be changed to connect to a remote router.
  • -v - Verbose output, can be given multiple times.

Debugging security token verification

The security token verification only logs messages when the log level is set to 4 or higher. Then it will only log some errors. It is possible to enable more verbose logging using the security-token-config that is installed together with the router.

When verbose logging is enabled, the router will log information about the token verification, including the configured token secrets, so it needs to be used with care.

The logged lines are prefixed with verify_security_token.

The security-token-config tool supports the commands print and set.

The print command prints the current configuration. If nothing is configured it will not print anything.

Set

The set command sets the configuration. The following parameters are supported:

security-token-config set
    [-d <enabled>]
  • -d <enabled> - A boolean option that specifies if debug logging should be enabled or not. The parameter accepts the values true and false.

1.5.4.5 - Subnets API

How to match clients into named subnets and use them in routing

ESB3024 Router provides utilities to quickly match clients into subnets. Any combination of IPv4 and IPv6 addresses can be used. To begin, a JSON file is needed, defining all subnets, e.g:

{
  "255.255.255.255/24": "area1",
  "255.255.255.255/16": "area2",
  "255.255.255.255/8": "area3",
  "90.90.1.3/16": "area4",
  "5.5.0.4/8": "area5",
  "2a02:2e02:9bc0::/48": "area6",
  "2a02:2e02:9bc0::/32": "area7",
  "2a02:2e02:9bc0::/16": "area8",
  "2a02:2e02:9de0::/44": "combined_area",
  "2a02:2e02:ada0::/44": "combined_area"
}

and PUT it to the endpoint :5001/v1/subnets or :5001/v2/subnets, the API version doesn’t matter for subnets:

curl -k -T subnets.json -H "Content-Type: application/json" https://router-host:5001/v1/subnets

Note that it is possible for several subnet CIDR strings to share the same label, effectively grouping them together.

This will load the subnets into the router which will then be usable within any Lua functions, accessed from the request and session tables respectively, e.g.

{
  "routing": {
    "id": "routing_table",
    "member_order": "sequential",
    "members": [
      {
        "id": "node1",
        "host_id": "host1",
        "weight_function": "return request.subnet == 'area1' and 1 or 0"
      }
    ]
  }
}

Subnet matching will use the client IP fetched from the request or session tables. When possible, the subnet with the longest matching subnet mask will be chosen, i.e. 255.255.255.255/28will be chosen over 255.255.255.255/24. If no matching subnets are found, the boolean value false will be returned.

NOTE: To use booleans in strings in Lua, calling tostring(bool) is required. Therefore, since subnet lookup might return false, the subnet call should be wrapped as: tostring(session.subnet) or tostring(requst.subnet).

Invalid ip-addresses will be omitted during subnet list construction accompanied by a message in the log displaying the invalid IP address.

1.5.4.6 - Lua Features

Detailed descriptions and examples of Lua features offered by ESB3024 Router.

1.5.4.6.1 - Global Lua Tables

Details on all global Lua tables and the data they contain.

There are multiple global tables containing important data available while writing Lua code for the router.

selection_input

Contains arbitrary, custom fields fed into the router by clients, see API overview for details on how to inject data into this table.

Note that the selection_input table is iterable.

Usage examples:

print(selection_input['some_value'])

-- Iterate over table
if selection_input then
    for k, v in pairs(selection_input) do
        print('here is '..'selection_input!')
        print(k..'='..v)
    end
else
    print('selection_input is nil')
end

session_groups

Defines a mapping from session group name to boolean, indicating whether the session belongs to the session group or not.

Usage examples:

if session_groups.vod then print('vod') else print('not vod') end
if session_groups['vod'] then print('vod') else print('not vod') end

session_count

Provides counters of number of session types per session group. The table uses the structure qoe_score.<session_type>.<session_group>.

Usage examples:

print(session_count.instream.vod)
print(session_count.initial.vod)

qoe_score

Provides the quality of experience score per host per session group. The table uses the structure qoe_score.<host>.<session_group>.

Usage examples:

print(qoe_score.host1.vod)
print(qoe_score.host1.live)

request

Contains data related to the HTTP request between the client and the router.

  • request.method
    • Description: HTTP request method.
    • Type: string
    • Example: 'GET', 'POST'
  • request.body
    • Description: HTTP request body string.
    • Type: string or nil
    • Example: '{"foo": "bar"}'
  • request.major_version
    • Description: Major HTTP version such as x in HTTP/x.1.
    • Type: integer
    • Example: 1
  • request.minor_version
    • Description: Minor HTTP version such as x in HTTP/1.x.
    • Type: integer
    • Example: 1
  • request.protocol
    • Description: Transfer protocol variant.
    • Type: string
    • Example: 'HTTP', 'HTTPS'
  • request.client_ip
    • Description: IP address of the client issuing the request.
    • Type: string
    • Example: '172.16.238.128'
  • request.path_with_query_params
    • Description: Full request path including query parameters.
    • Type: string
    • Example: '/mycontent/superman.m3u8?b=y&c=z&a=x'
  • request.path
    • Description: Request path without query parameters.
    • Type: string
    • Example: '/mycontent/superman.m3u8'
  • request.query_params
    • Description: The query parameter string.
    • Type: string
    • Example: 'b=y&c=z&a=x'
  • request.filename
    • Description: The part of the path following the final slash, if any.
    • Type: string
    • Example: 'superman.m3u8'
  • request.subnet
    • Description: Subnet of client_ip.
    • Type: string or nil
    • Example: 'all'

session

Contains data related to the current session.

  • session.client_ip
    • Description: Alias for request.client_ip. See documentation for table request above.
  • session.path_with_query_params
    • Description: Alias for request.path_with_query_params. See documentation for table request above.
  • session.path
    • Description: Alias for request.path. See documentation for table request above.
  • session.query_params
    • Description: Alias for request.query_params. See documentation for table request above.
  • session.filename
    • Description: Alias for request.filename. See documentation for table request above.
  • session.subnet
    • Description: Alias for request.subnet. See documentation for table request above.
  • session.host
    • Description: ID of the currently selected host for the session.
    • Type: string or nil
    • Example: 'host1'
  • session.id
    • Description: ID of the session.
    • Type: string
    • Example: '8eb2c1bdc106-17d2ff-00000000'
  • session.session_type
    • Description: Type of the session.
    • Type: string
    • Example: 'initial' or 'instream'. Identical to the value of the Type argument of the session translation function.
  • session.is_managed
    • Description: Identifies managed sessions.
    • Type: boolean
    • Example: true if Type/session.session_type is 'instream'

request_headers

Contains the headers from the request between the client and the router, keyed by name.

Usage example:

print(request_headers['User-Agent'])

request_query_params

Contains the query parameters from the request between the client and the router, keyed by name.

Usage example:

print(request_query_params.a)

session_query_params

Alias for metatable request_query_params.

response

Contains data related to the outgoing response apart from the headers.

  • response.body
    • Description: HTTP response body string.
    • Type: string or nil
    • Example: '{"foo": "bar"}'
  • response.code
    • Description: HTTP response status code.
    • Type: integer
    • Example: 200, 404
  • response.text
    • Description: HTTP response status text.
    • Type: string
    • Example: 'OK', 'Not found'
  • response.major_version
    • Description: Major HTTP version such as x in HTTP/x.1.
    • Type: integer
    • Example: 1
  • response.minor_version
    • Description: Minor HTTP version such as x in HTTP/1.x.
    • Type: integer
    • Example: 1
  • response.protocol
    • Description: Transfer protocol variant.
    • Type: string
    • Example: 'HTTP', 'HTTPS'

response_headers

Contains the response headers keyed by name.

Usage example:

print(response_headers['User-Agent'])

1.5.4.6.2 - Health Check Functions

Built in Lua health check functions

This section details built in Lua functions that are meant to be used for host health checks. Note that these functions rely on data supplied by metric agents detailed in Cache hardware metrics: monitoring and routing. Make sure cache hardware metrics are supplied to the router before using any of these functions.

cpu_load_ok()

Parameters

The function accepts an optional argument table with the following keys:

  • Optional hostname: The name of the host. Defaults to the hostname of the selected host if not provided.
  • Optional cpu_load5_limit: The acceptable limit for the 5-minute CPU load. Defaults to 0.9 if not provided.

Returns

The function returns 1 if the five minute CPU load average is below their respective limits, and 0 otherwise.

Usage examples

cpu_load_ok()
cpu_load_ok({hostname = "custom_host"})
cpu_load_ok({cpu_load5_limit = 0.8})
cpu_load_ok({hostname = "custom_host", cpu_load5_limit = 0.8})

memory_usage_ok()

Parameters

The function accepts an optional argument table with the following keys:

  • Optional hostname: The name of the host. Defaults to the hostname of the selected host if not provided.
  • Optional memory_usage_limit: The acceptable limit for the memory usage. Defaults to 0.9 if not provided.

Returns

The function returns 1 if the memory usage is below the limit, and 0 otherwise.

Usage examples

memory_usage_ok()
memory_usage_ok({hostname = "custom_host"})
memory_usage_ok({memory_usage_limit = 0.7})
memory_usage_ok({hostname = "custom_host", memory_usage_limit = 0.7})

interfaces_online()

Parameters

The function accepts an argument table with the following keys:

  • Required interfaces: A string or a table of strings representing the network interfaces to check.
  • Optional hostname: The name of the host. Defaults to the hostname of the selected host if not provided.

Returns

The function returns 1 if all the specified interfaces are online, and 0 otherwise.

Usage examples

interfaces_online({interfaces = "eth0"})
interfaces_online({interfaces = {"eth0", "eth1"}})
interfaces_online({hostname = "custom_host", interfaces = "eth0"})
interfaces_online({hostname = "custom_host", interfaces = {"eth0", "eth1"}})

health_check()

Parameters

The function accepts an optional argument table with the following keys:

  • Required interfaces: A string or a table of strings representing the network interfaces to check.
  • Optional hostname: The name of the host. Defaults to the hostname of the selected host if not provided.
  • Optional cpu_load5_limit: The acceptable limit for the 5-minute CPU load. Defaults to 0.9 if not provided.
  • Optional memory_usage_limit: The acceptable limit for the memory usage. Defaults to 0.9 if not provided.

Returns

The function returns 1 if all the specified interfaces are online, and 0 otherwise.

Usage examples

health_check({interfaces = "eths0"})
health_check({hostname = "custom_host", interfaces = "eths0"})
health_check({cpu_load5_limit = 0.7, memory_usage_limit = 0.8, interfaces = "eth0"})
health_check({hostname = "custom_host", cpu_load5_limit = 0.7, memory_usage_limit = 0.8, interfaces = {"eth0", "eth1"}})

1.5.4.6.3 - Request Translation Function

Instructions for how to write a function to modify incoming requests before routing decisions are being made.

Specifies the body of a Lua function that inspects every incoming HTTP request and overwrites individual fields before further processing by the router.

Returns nil when nothing is to be changed, or HTTPRequest(t) where t is a table with any of the following optional fields:

  • Method
    • Description: Replaces the HTTP request method in the request being processed.
    • Type: string
    • Example: 'GET', 'POST'
  • Path
    • Description: Replaces the request path in the request being processed.
    • Type: string
    • Example: '/mycontent/superman.m3u8'
  • ClientIp
    • Description: Replaces client IP address in the request being processed.
    • Type: string
    • Example: '172.16.238.128'
  • Body
    • Description: Replaces body in the request being processed.
    • Type: string or nil
    • Example: '{"foo": "bar"}'
  • QueryParameters
    • Description: Adds, removes or replaces individual query parameters in the request being processed.
    • Type: nested table (indexed by number) representing an array of query parameters as {[1]='Name',[2]='Value'} pairs that are added to the request being processed, or overwriting existing query parameters with colliding names. To remove a query parameter from the request, specify nil as value, i.e. QueryParameters={..., {[1]='foo',[2]=nil} ...}. Returning a query parameter with a name but no value, such as a in the request '/index.m3u8?a&b=22' is currently not supported.
  • Headers
    • Description: Adds, removes or replaces individual headers in the request being processed.
    • Type: nested table (indexed by number) representing an array of request headers as {[1]='Name',[2]='Value'} pairs that are added to the request being processed, or overwriting existing request headers with colliding names. To remove a header from the request, specify nil as value, i.e. Headers={..., {[1]='foo',[2]=nil} ...}. Duplicate names are supported. A multi-value header such as Foo: bar1,bar2 is defined by specifying Headers={..., {[1]='foo',[2]='bar1'}, {[1]='foo',[2]='bar2'}, ...}.

Example of a request_translation_function body that sets the request path to a hardcoded value and adds the hardcoded query parameter a=b:

-- Statements go here
print('Setting hardcoded Path and QueryParameters')
return HTTPRequest({
  Path = '/content.mpd',
  QueryParameters = {
    {'a','b'}
  }
})

Arguments

The following (iterable) arguments will be known by the function:

QueryParameters

  • Type: nested table (indexed by number).

  • Description: Array of query parameters as {[1]='Name',[2]='Value'} pairs that were present in the query string of the request. Format identical to the HTTPRequest.QueryParameters-field specified for the return value above.

  • Example usage:

    for _, queryParam in pairs(QueryParameters) do
      print(queryParam[1]..'='..queryParam[2])
    end
    

Headers

  • Type: nested table (indexed by number).

  • Description: Array of request headers as {[1]='Name',[2]='Value'} pairs that were present in the request. Format identical to the HTTPRequest.Headers-field specified for the return value above. A multi-value header such as Foo: bar1,bar2 is seen in request_translation_function as Headers={..., {[1]='foo',[2]='bar1'}, {[1]='foo',[2]='bar1'}, ...}.

  • Example usage:

    for _, header in pairs(Headers) do
      print(header[1]..'='..header[2])
    end
    

Additional data

In addition to the arguments above, the following Lua tables, documented in Global Lua Tables, provide additional data that is available when executing the request translation function:

If the request translation function modifies the request, the request, request_query_params and request_headers tables will be updated with the modified request and made available to the routing rules.

1.5.4.6.4 - Session Translation Function

Instructions for how to write a function to modify a client session to affect how it is handled by the router.

Specifies the body of a Lua function that inspects a newly created session and may override its suggested type from “initial” to “instream” or vice versa. A number of helper functions are provided to simplify changing the session type.

Returns nil when the session type is to remain unchanged, or Session(t) where t is a table with a single field:

  • Type
    • Description: New type of the session.
    • Type: string
    • Example: 'instream', 'initial'

Basic Configuration

It is possible to configure the maximum number of simultaneous managed sessions on the router. If the maximum number is reached, no more managed sessions can be created. Using confcli, it can be configured by running

$ confcli services.routing.tuning.general.maxActiveManagedSessions
{
    "maxActiveManagedSessions": 1000
}
$ confcli services.routing.tuning.general.maxActiveManagedSessions 900
services.routing.tuning.general.maxActiveManagedSessions = 900

Common Arguments

While executing the session translation function, the following arguments are available:

  • Type: The current type of the session ('instream' or 'initial').

Usage examples:

-- Flip session type
local newType = 'initial'
if Type == 'initial' then
    newType = 'instream'
end
print('Changing session type from ' .. Type .. ' to ' .. newType)
return Session({['Type'] = newType})

Session Translation Helper Functions

The standard Lua library prodives four helper functions to simplify the configuration of the session translation function:

set_session_type(session_type)

This function will set the session type to the supplied session_type and the maximum number of sessions of that type has not been reached.

Parameters

  • session_type: The type of session to create, possible values are ‘initial’ or ‘instream’.

Usage Examples

return set_session_type('instream')
return set_session_type('initial')

set_session_type_if_in_group(session_type, session_group)

This function will set the session type to the supplied session_type if the session is part of session_group and the maximum number of sessions of that type has not been reached.

Parameters

  • session_type: The type of session to create, possible values are ‘initial’ or ‘instream’.
  • session_group: The name of the session group.

Usage Examples

return set_session_type_if_in_group('instream', 'sg1')

set_session_type_if_in_all_groups(session_type, session_groups)

This function will set the session type to the supplied session_type if the session is part of all session groups given by session_groups and the maximum number of sessions of that type has not been reached.

Parameters

  • session_type: The type of session to create, possible values are ‘initial’ or ‘instream’.
  • session_groups: A list of session group names.

Usage Examples

return set_session_type_if_in_all_groups('instream', {'sg1', 'sg2'})

set_session_type_if_in_any_group(session_type)

This function will set the session type to the supplied session_type if the session is part of one or more of the session groups given by session_groups and the maximum number of sessions of that type has not been reached.

Parameters

  • session_type: The type of session to create, possible values are ‘initial’ or ‘instream’.
  • session_groups: A list of session group names.

Usage Examples

return set_session_type_if_in_any_group('instream', {'sg1', 'sg2'})

Configuration

Using confcli, example of how the functions above can be used in the session translation function can be configured by running any of

$ confcli services.routing.translationFunctions.session "return set_session_type('instream')"
services.routing.translationFunctions.session = "return set_session_type('instream')"

$ confcli services.routing.translationFunctions.session "return set_session_type_if_in_group('instream', 'sg1')"
services.routing.translationFunctions.session = "return set_session_type_if_in_group('instream', 'sg1')"

$ confcli services.routing.translationFunctions.session "return set_session_type_if_in_all_groups('instream', {'sg1', 'sg2'})"
services.routing.translationFunctions.session = "return set_session_type_if_in_all_groups('instream', {'sg1', 'sg2'})"

$ confcli services.routing.translationFunctions.session "return set_session_type_if_in_any_group('instream', {'sg1', 'sg2'})"
services.routing.translationFunctions.session = "return set_session_type_if_in_any_group('instream', {'sg1', 'sg2'})"

Additional data

In addition to the arguments above, the following Lua tables, documented in Global Lua Tables, provide additional data that is available when executing the response translation function:

The selection_input table will not change while a routing request is handled. A request_translation_function and the corresponding response_translation_function will see the same selection_input table, even if the selection data is updated while the request is being handled.

1.5.4.6.5 - CDN Request Translation Function

Instructions on how to write a function to modify requests that are sent to redirecting CDNs.

Specifies the body of a Lua function that inspects every HTTP request that is sent to a redirecting CDN and overwrites individual fields before it is sent to the CDN.

Returns nil when nothing is to be changed, or HTTPRequest(t) where t is a table with any of the following optional fields:

  • Method
    • Description: Replaces the HTTP request method in the request being processed.
    • Type: string
    • Example: 'GET', 'POST'
  • Path
    • Description: Replaces the request path in the request being processed.
    • Type: string
    • Example: '/mycontent/superman.m3u8'
  • Body
    • Description: Replaces body in the request being processed.
    • Type: string or nil
    • Example: '{"foo": "bar"}'
  • QueryParameters
    • Description: Adds, removes or replaces individual query parameters in the request being processed.
    • Type: nested table (indexed by number) representing an array of query parameters as {[1]='Name',[2]='Value'} pairs that are added to the request being processed, or overwriting existing query parameters with colliding names. To remove a query parameter from the request, specify nil as value, i.e. QueryParameters={..., {[1]='foo',[2]=nil} ...}. Returning a query parameter with a name but no value, such as a in the request '/index.m3u8?a&b=22' is currently not supported.
  • Headers
    • Description: Adds, removes or replaces individual headers in the request being processed.
    • Type: nested table (indexed by number) representing an array of request headers as {[1]='Name',[2]='Value'} pairs that are added to the request being processed, or overwriting existing request headers with colliding names. To remove a header from the request, specify nil as value, i.e. Headers={..., {[1]='foo',[2]=nil} ...}. Duplicate names are supported. A multi-value header such as Foo: bar1,bar2 is defined by specifying Headers={..., {[1]='foo',[2]='bar1'}, {[1]='foo',[2]='bar2'}, ...}.
  • Host
    • Description: Replaces the host that the request is sent to.
    • Type: string
    • Example: 'new-cdn.example.com', '192.0.2.7'
  • Port
    • Description: Replaces the TCP port that the request is sent to.
    • Type: number
    • Example: 8081
  • Protocol
    • Description: Decides which protocol that will be used for sending the request. Valid protocols are 'HTTP' and 'HTTPS'.
    • Type: string
    • Example: 'HTTP', 'HTTPS'

Example of a cdn_request_translation_function body that sets the request path to a hardcoded value and adds the hardcoded query parameter a=b:

-- Statements go here
print('Setting hardcoded Path and QueryParameters')
return HTTPRequest({
  Path = '/content.mpd',
  QueryParameters = {
    {'a','b'}
  }
})

Arguments

The following (iterable) arguments will be known by the function:

QueryParameters

  • Type: nested table (indexed by number).

  • Description: Array of query parameters as {[1]='Name',[2]='Value'} pairs that are present in the query string of the request from the client to the router. Format identical to the HTTPRequest.QueryParameters-field specified for the return value above.

  • Example usage:

    for _, queryParam in pairs(QueryParameters) do
      print(queryParam[1]..'='..queryParam[2])
    end
    

Headers

  • Type: nested table (indexed by number).

  • Description: Array of request headers as {[1]='Name',[2]='Value'} pairs that are present in the request from the client to the router. Format identical to the HTTPRequest.Headers-field specified for the return value above. A multi-value header such as Foo: bar1,bar2 is seen in cdn_request_translation_function as Headers={..., {[1]='foo',[2]='bar1'}, {[1]='foo',[2]='bar1'}, ...}.

  • Example usage:

    for _, header in pairs(Headers) do
      print(header[1]..'='..header[2])
    end
    

Global tables

The following non-iterable global tables are available for use by the cdn_request_translation_function.

Table outgoing_request

The outgoing_request table contains the request that is to be sent to the redirecting CDN.

  • outgoing_request.method
    • Description: HTTP request method.
    • Type: string
    • Example: 'GET', 'POST'
  • outgoing_request.body
    • Description: HTTP request body string.
    • Type: string or nil
    • Example: '{"foo": "bar"}'
  • outgoing_request.major_version
    • Description: Major HTTP version such as x in HTTP/x.1.
    • Type: integer
    • Example: 1
  • outgoing_request.minor_version
    • Description: Minor HTTP version such as x in HTTP/1.x.
    • Type: integer
    • Example: 1
  • outgoing_request.protocol
    • Description: Transfer protocol variant.
    • Type: string
    • Example: 'HTTP', 'HTTPS'

Table outgoing_request_headers

Contains the request headers from the request that is to be sent to the redirecting CDN, keyed by name.

Example:

print(outgoing_request_headers['X-Forwarded-For'])

Multiple values are separated with a comma.

Additional data

In addition to the arguments above, the following Lua tables, documented in Global Lua Tables, provide additional data that is available when executing the request translation function:

1.5.4.6.6 - Response Translation Function

Instructions for how to write a function to modify outgoing responses after a routing decision has been made.

Specifies the body of a Lua function that inspects every outgoing HTTP response and overwrites individual fields before being sent to the client.

Returns nil when nothing is to be changed, or HTTPResponse(t) where t is a table with any of the following optional fields:

  • Code
    • Description: Replaces status code in the response being sent.
    • Type: integer
    • Example: 200, 404
  • Text
    • Description: Replaces status text in the response being sent.
    • Type: string
    • Example: 'OK', 'Not found'
  • MajorVersion
    • Description: Replaces major HTTP version such as x in HTTP/x.1 in the response being sent.
    • Type: integer
    • Example: 1
  • MinorVersion
    • Description: Replaces minor HTTP version such as x in HTTP/1.x in the response being sent.
    • Type: integer
    • Example: 1
  • Protocol
    • Description: Replaces protocol in the response being sent.
    • Type: string
    • Example: 'HTTP', 'HTTPS'
  • Body
    • Description: Replaces body in the response being sent.
    • Type: string or nil
    • Example: '{"foo": "bar"}'
  • Headers
    • Description: Adds, removes or replaces individual headers in the response being sent.
    • Type: nested table (indexed by number) representing an array of response headers as {[1]='Name',[2]='Value'} pairs that are added to the response being sent, or overwriting existing request headers with colliding names. To remove a header from the response, specify nil as value, i.e. Headers={..., {[1]='foo',[2]=nil} ...}. Duplicate names are supported. A multi-value header such as Foo: bar1,bar2 is defined by specifying Headers={..., {[1]='foo',[2]='bar1'}, {[1]='foo',[2]='bar2'}, ...}.

Example of a response_translation_function body that sets the Location header to a hardcoded value:

-- Statements go here
print('Setting hardcoded Location')
return HTTPResponse({
  Headers = {
    {'Location', 'cdn1.com/content.mpd?a=b'}
  }
})

Arguments

The following (iterable) arguments will be known by the function:

Headers

  • Type: nested table (indexed by number).

  • Description: Array of response headers as {[1]='Name',[2]='Value'} pairs that are present in the response being sent. Format identical to the HTTPResponse.Headers-field specified for the return value above. A multi-value header such as Foo: bar1,bar2 is seen in response_translation_function as Headers={..., {[1]='foo',[2]='bar1'}, {[1]='foo',[2]='bar1'}, ...}.

  • Example usage:

    for _, header in pairs(Headers) do
      print(header[1]..'='..header[2])
    end
    

Additional data

In addition to the arguments above, the following Lua tables, documented in Global Lua Tables, provide additional data that is available when executing the response translation function:

1.5.5 - Confd Auto Upgrade Tool

Applying automatic configuration migrations

The confd-auto-upgrade tool is a simple utility to automatically migrate the confd configuration schema between different versions of the Director. Starting with version 1.12.0, it is possible to automatically apply the necessary configuration changes in a controlled and predictable manner. While this tool is intended to help transition the configuration format between the different versions, it is not a substitute for proper backups, and while downgrading to an earlier version, it may not be possible to recover previously modified or deleted configuration values.

When using the tool, both the “from” and “to” versions must be specified. Internally, the tool will calculate a list of migrations which must be applied to transition between the given versions, and apply them, outputting the final configuration to standard output. The current configuration can either be piped in to the tool via standard input, or supplied as a static file. Providing a “from” version which is later than the “to” version will result in the downgrade migrations being applied in reverse order, effectively downgrading the configuration to the lower version.

For convenience, the tool is deployed to the ACD Nodes automatically at install time as a standard Docker or Podman container, however since it is not intended to run as a service, only the image will be present, not a running container.

Determining the Image Tag.

Each version of the router will come with a new version of the confd-auto-upgrade tool as a docker image. Because the migration scripts encoded within the tool itself, it is important to ensure that the tagged version of the tool in use matches at least the latest version of the router. I.e. if you are upgrading from 1.10.0 to 1.12.0, then the version of the tool from 1.12.0 or later must be used, since the version of the tool from 1.10.0 would not have the adequate migration scripts included.

To determine which versions of the tool are present on the node, execute the following:

$> podman images
REPOSITORY                                   TAG                         IMAGE ID      CREATED        SIZE
images.edgeware.tv/orc-re-master             20240513T082529Z-c97ff528c  dc757aee88aa  17 hours ago   599 MB
images.edgeware.tv/convoy-bridge-master      20240513T082529Z-c97ff528c  b7d950838a1e  17 hours ago   106 MB
images.edgeware.tv/confd-transformer-master  20240513T082529Z-c97ff528c  d6acde159e8f  17 hours ago   560 MB
images.edgeware.tv/auto-upgrade-master       20240513T082529Z-c97ff528c  0a49a721a63d  17 hours ago   1.04 GB
images.edgeware.tv/acd-confd-master          20240513T082529Z-c97ff528c  b10765a95d0a  17 hours ago   308 MB
localhost/grafana/grafana                    10.4.2                      679e4be9f918  4 weeks ago    437 MB
images.edgeware.tv/edns-proxy                latest                      e7153c8f8a9f  5 months ago   20.9 MB
localhost/prom/alertmanager                  v0.25.0                     c8568f914cd2  16 months ago  66.5 MB
localhost/grafana/loki                       2.6.1                       42dd24636051  22 months ago  62.4 MB
localhost/fluent/fluent-bit                  1.9.6                       444ce20a268d  22 months ago  69 MB
localhost/prom/prometheus                    v2.35.0                     a5bac665ffa2  2 years ago    207 MB

Note the tag for “images.edgeware.tv/auto-upgrade-master” matches the tag of the “images.edgeware.tv/orc-re-master” image.

Performing the Upgrade

In the following example scenario, a system with version 1.10.1 has been upgraded to 1.12.0. Before upgrading a backup of the configuration was taken and saved to current_config.json.

Using the image and tag as determined in the above section. Issue the following command:

cat current_config.json | \
  podman run -i --rm images.edgeware.tv/auto-upgrade-master:20240513T082529Z-c97ff528c \
  --in - --from 1.10.1 --to 1.12.0 \
  | tee upgraded_config.json

In the above example, the updated configuration is saved to upgraded_config.json. It is recommended to manually verify the generated configuration, and after which apply the config to confd by using cat upgraded_config.json | confcli -i.

It is also possible to combine the two commands, by piping the output of the auto-upgrade tool directly to confcli -i. E.g.

cat current_config.json | podman run ... | tee upgraded_config.json | confcli -i

This will save a backup of the upgraded configuration to upgraded_config.json and at the same time apply the changes to confd immediately.

Downgrading the Configuration

The steps for downgrading the configuration are exactly the same as for upgrade except for the --from and --to versions should be swapped. E.g. --from 1.12.0 --to 1.10.1. Keep in mind however, that during an upgrade some configuration properties may have been deleted or modified, and while downgrading over those steps, some data loss may occur. In those cases, it may be easier and safer to simply restore from backup. In most cases where configuration properties are removed during upgrade, the corresponding downgrade will simply restore the default values of those properties.

1.6 - Operations

Operators Guide

This guide describes how to perform day-to-day operations of the ACD Router and its associated services, collectively known as the Director.

Component Overview

To effectively operate the Director software, it is important to understand the composition of the various software components and how they are deployed.

Each Director instance functions as an independent system, comprising multiple containerized services. These containers are managed by a standard container runtime and are seamlessly integrated with the host’s operating system to enhance the overall operator experience.

For Red Hat Enterprise Linux 8 based operating systems, the Podman container runtime is used for container management. In the case of older Red Hat releases, Docker serves as the container runtime. Although both

runtimes

utilize the same OCI compliant container images and offer equivalent levels of abstraction, performance, and security, the key distinction lies in Podman’s ability to operate without an additional daemon service running on the host. Unlike Docker, Podman manages each container as a separate process, eliminating the reliance on a shared daemon and mitigating the risk of a single-point-of-failure scenario.

Although several distinct services make up the Director, the primary component is the router. The router is responsible for listening for incoming requests, processing the request, and redirecting the client to the appropriate host, or CDN to deliver the requested content.

Two additional containers are responsible for configuration management. Those are confd and confd-transformer. The former manages a local database of configuration metadata and provides a REST API for managing the configuration. The confd-transformer simply listens for configuration changes from confd and adapts that configuration to a format suitable for the router to ingest. For additional information about setting up and using confd see here..

The next two components, the edns-proxy and the convoy-bridge allow the router to communicate with an EDNS server for EDNS-based routing, and with synchronization with Convoy respectively. Additional information about the EDNS-Proxy is available here.. For the Convoy Bridge service see here..

The remaining containers are useful for metrics, monitoring, and alerting. These include prometheus and grafana for monitoring and analytics, fluentbit and alertmanager for monitoring and alarms, and grafana-loki for log aggregation.

1.6.1 - Services

Starting / Stopping / Monitoring Services

Each container shipped with the Director is fully-integrated with the systemd service on the host, enabling easy management using standard systemd commands. The logs for each container are also full-integrated with journald to simplify troubleshooting.

In order to integrate the Podman containers with systemd, a common prefix of acd- has been applied to each service name. For example the router container is managed by the service acd-router, and the confd container is managed by the service acd-confd. These same prefixed names apply while fetching logs via journald. This common prefix aids in grouping the related services as well as provides simpler filtering for tab-completion.

Starting / Stopping Services

Standard systemd commands should be used to start and stop the services.

  • systemctl start acd-router - Starts the router container.
  • systemctl stop acd-router - Stops the router container.
  • systemctl status acd-router - Displays the status of the router container.

Due to the limitation of needing the acd- prefix, it provides the ability to work with all ACD services in a group. For example:

  • systemctl status 'acd-*' - Display the status of all installed ACD components.
  • systemctl start 'acd-*' - Start all ACD components.

Logging

Each ACD component corresponds to a journal entry with the same unit name, with the acd- prefix. Standard journald commands can be used to view and manage the logging.

  • journalctl -u acd-router - Display the logs for the router container

Access Log

Access logs can be obtained from journald by using the following command:

journalctl SYSLOG_IDENTIFIER=router ACCESSLOG=1

This will output the router’s access logs in a standard format.

Troubleshooting

Some additional logging may be available in the filesystem, the paths of which can be determined by executing the ew-sysinfo command. See Diagnostics. for additional details.

1.6.2 - Docker

Special operating instructions for Red Hat Enterprise Linux 7

Support for Red Hat Enterprise Linux 7 and compatible Operating Systems is considered best-effort and the instructions included here are only maintained for archival purposes.

Since Red Hat Enterprise Linux 7 uses the Docker runtime, there are several key differences which are noted below.

Starting and Stopping Services

Since the containers are not integrated into systemd under Docker, standard Docker container management commands must be used to start and stop the services.

  • docker ps - Displays all running containers along with their relevant metadata.
  • docker stop router - Stops the router container.
  • docker start router - Starts the router container.

Obtaining container logs

The standard docker logs command should be used to view the logs for the various containers.

  • docker logs router - Display the complete log for the router container.
  • docker logs -f router - Display and tail the log for the router container.

Router Access Logs are not available under Docker.

1.7 - Convoy Bridge

Convoy Bridge Integration

The convoy-bridge is an optional integration service, pre-installed alongside the router which provides two-way communication between the router and a separate Convoy installation.

The convoy-bridge is designed to allow the Convoy account metadata to be available from within the router for such use-cases as inserting the account specific prefixes in the redirect URL and validating per-account internal security tokens. The service works by periodically polling the Convoy server for changes to the configuration, and when detected, the relevant configuration information is pushed to the router.

In addition, the convoy-bridge has the ability to integrate the router with the Convoy analytics service, such that client sessions started by the router are properly collected by Convoy, and are available in the dashboards.

Configuration

The convoy-bridge service is configured using confcli on the router host. All configuration for the convoy-bridge exists under the path integration.convoy.bridge.

{
  "logLevel": "info",
  "accounts": {
    "enabled": true,
    "dbUrl": "mysql://convoy:eith7jee@convoy:3306",
    "dbPollInterval": 60
  },
  "analytics": {
    "enabled": true,
    "brokers": ["broker1:9092", "broker2:9092"],
    "batchInterval": 10,
    "maxBatchSize": 500
  },
  "otherRouters": [
    {
      "url": "https://router2:5001",
      "apiKey": "key1",
      "validateCerts": true
    }
  ]
}

In the above configuration block, there are three main sections. The accounts section enables fetching account metadata from Convoy towards the router. The analytics section controls the integration between the router and the Convoy analytics service. The otherRouters section is used to synchronize additional router instances. The local router instance will always be implicitly included. Additional routers listed in this section will be handled by this instance of the convoy-bridge service.

Logging

For RHEL8 or later, the logs are available in the system journal and can be viewed using:

journalctl -u acd-convoy-bridge

For RHEL7, logs are available from within Docker and can be viewed with the command:

docker logs convoy-bridge

1.8 - Monitoring

Monitoring

1.8.1 - System troubleshooting

Using ew-sysinfo to monitor and troubleshoot ESB3024

ESB3024 contains the tool ew-sysinfo that gives an overview of how the system is doing. Simply use the command and the tool will output information about the system and the installed ESB3024 services.

The output format can be changed using the --format flag, possible values are human (default) and json, e.g.:

$ ew-sysinfo
system:
   os: ['5.4.17-2136.321.4.el8uek.x86_64', 'Oracle Linux Server 8.8']
   cpu_cores: 2
   cpu_load_average: [0.03, 0.03, 0.0]
   memory_usage: 478 MB
   memory_load_average: [0.03, 0.03, 0.0]
   boot_time: 2023-09-08T08:30:57Z
   uptime: 6 days, 3:43:44.640665
   processes: 122
   open_sockets:
      ipv4: 12
      ipv6: 18
      ip_total: 30
      tcp_over_ipv4: 9
      tcp_over_ipv6: 16
      tcp_total: 25
      udp_over_ipv4: 3
      udp_over_ipv6: 2
      udp_total: 5
      total: 145
system_disk (/):
   total: 33271 MB
   used: 7978 MB (24.00%)
   free: 25293 MB
journal_disk (/run/log/journal):
   total: 1954 MB
   used: 217 MB (11.10%)
   free: 1736 MB
vulnerabilities:
   meltdown: Mitigation: PTI
   spectre_v1: Mitigation: usercopy/swapgs barriers and __user pointer sanitization
   spectre_v2: Mitigation: Retpolines, STIBP: disabled, RSB filling, PBRSB-eIBRS: Not affected
processes:
   orc-re:
      pid: 177199
      status: sleeping
      cpu_usage_percent: 1.0%
      cpu_load_average: 131.11%
      memory_usage: 14 MB (0.38%)
      num_threads: 10
hints:
   get_raw_router_config: cat /opt/edgeware/acd/router/cache/config.json
   get_confd_config: cat /opt/edgeware/acd/confd/store/__active
   get_router_logs: journalctl -u acd-router
   get_edns_proxy_logs: journalctl -u acd-edns-proxy
   check_firewall_status: systemctl status firewalld
   check_firewall_config: iptables -nvL
# For --format=json, it's recommended to pipe the output to a JSON interpreter
# such as jq

$ ew-sysinfo --format=json | jq
{
  "system": {
    "os": [
      "5.4.17-2136.321.4.el8uek.x86_64",
      "Oracle Linux Server 8.8"
    ],
    "cpu_cores": 2,
    "cpu_load_average": [
      0.01,
      0.0,
      0.0
    ],
    "memory_usage": "479 MB",
    "memory_load_average": [
      0.01,
      0.0,
      0.0
    ],
    "boot_time": "2023-09-08 08:30:57",
    "uptime": "6 days, 5:12:24.617114",
    "processes": 123,
    "open_sockets": {
      "ipv4": 13,
      "ipv6": 18,
      "ip_total": 31,
      "tcp_over_ipv4": 10,
      "tcp_over_ipv6": 16,
      "tcp_total": 26,
      "udp_over_ipv4": 3,
      "udp_over_ipv6": 2,
      "udp_total": 5,
      "total": 146
    }
  },
  "system_disk (/)": {
    "total": "33271 MB",
    "used": "7977 MB (24.00%)",
    "free": "25293 MB"
  },
  "journal_disk (/run/log/journal)": {
    "total": "1954 MB",
    "used": "225 MB (11.50%)",
    "free": "1728 MB"
  },
  "vulnerabilities": {
    "meltdown": "Mitigation: PTI",
    "spectre_v1": "Mitigation: usercopy/swapgs barriers and __user pointer sanitization",
    "spectre_v2": "Mitigation: Retpolines, STIBP: disabled, RSB filling, PBRSB-eIBRS: Not affected"
  },
  "processes": {
    "orc-re": {
      "pid": 177199,
      "status": "sleeping",
      "cpu_usage_percent": "0.0%",
      "cpu_load_average": "137.63%",
      "memory_usage": "14 MB (0.38%)",
      "num_threads": 10
    }
  }
}

Note that your system might have different monitored processes and field names.

The field hints is different from the rest. It lists common commands that can be used to further monitor system performance, useful for quickly troubleshooting a faulty system.

1.8.2 - Scraping data with Prometheus

Prometheus is a third-party data scraper which is installed as a containerized service in the default installation of ESB3024 Router. It periodically reads metrics data from different services, such as acd-router, aggregates it and makes it available to other services that visualize the data. Those services include Grafana and Alertmanager.

The Prometheus configuration file can be found on the host at /opt/edgeware/acd/prometheus/prometheus.yaml.

Accessing Prometheus

Prometheus has a web interface that is listening for HTTP connections on port 9090. There is no authentication, so anyone who has access to the host that is running Prometheus can access the interface.

Starting / Stopping Prometheus

After the service is configured, it can be managed via systemd, under the service unit acd-prometheus.

systemctl start acd-prometheus

For EL7 systems running under Docker, the container must be started or stopped using the respective Docker start/stop commands. Note that the acd- prefix is not applicable under Docker.

docker start prometheus

Logging

The container logs are automatically published to the system journal, under the same unit descriptor, and can be viewed using journalctl

journalctl -u acd-prometheus

For EL7 systems running under Docker, the container logs can only be viewed using the docker logs command. Note that the acd- prefix is not applicable under Docker.

docker logs prometheus

1.8.3 - Visualizing data with Grafana

1.8.3.1 - Managing Grafana

Grafana displays graphs based on data from Prometheus. A default deployment of Grafana is running in a container alongside ESB3024 Router.

Grafana’s configuration and runtime files are stored under /opt/edgeware/acd/grafana. It comes with default dashboards that are documented at Grafana dashboards.

Accessing Grafana

Grafana’s web interface is listening for HTTP connections on port 3000. It has two default accounts, edgeware and admin.

The edgeware account can only view graphs, while the admin account can also edit graphs. The accounts with default passwords are shown in the table below.

AccountDefault password
edgewareedgeware
adminedgeware

Starting / Stopping Grafana

Grafana can be managed via systemd, under the service unit acd-grafana.

systemctl start acd-grafana

For EL7 systems running under Docker, the container must be started or stopped using the respective Docker start/stop commands. Note that the acd- prefix is not applicable under Docker.

docker start grafana

Logging

The container logs are automatically published to the system journal, under the same unit descriptor, and can be viewed using journalctl

journalctl -u acd-grafana

For EL7 systems running under Docker, the container logs can only be viewed using the docker logs command. Note that the acd- prefix is not applicable under Docker.

docker logs grafana

1.8.3.2 - Grafana Dashboards

Dashboards in default Grafana installation

Grafana will be populated with pre-configured graphs which present some metrics on a time scale. Below is a comprehensive list of those dashboards, along with short descriptions.

Router Monitoring dashboard

This dashboard is by default set as home directory - it’s what user will see after logging in.

Number Of Initial Routing Decisions

HTTP Status Codes

Total number of responses sent back to incoming requests, shown by their status codes. Metric: client-response-status

Incoming HTTP and HTTPS Requests

Total number of incoming requests that were deemed valid, divided into SSL and Unencrypted categories. Metric: num_valid_http_requests

Debugging Information dashboard

Number of Lua Exceptions

Number of exceptions encountered so far while evaluating Lua rules. Metric: lua_num_errors

Number of Lua Contexts

Number of active Lua interpreters, both running and idle. Metric: lua_num_evaluators

Time Spent In Lua

Number of microseconds the Lua interpreters were running. Metric: lua_time_spent

Router Latencies

Histogram-like graph showing how many responses were sent within the given latency interval. Metric: orc_latency_bucket

Internal debugging

A folder that contains dashboards intended for internal use.

ACD: Incoming Internet Connections dashboard

SSL Warnings

Rate of warnings logged during TLS connections Metric: num_ssl_warnings_total

SSL Errors

Rate of errors logged during TLS connections Metric: num_ssl_errors_total

Valid Internet HTTPS Requests

Rate of incoming requests that were deemed valid, HTTPS only. Metric: num_valid_http_requests

Invalid Internet HTTPS Requests

Rate of incoming requests that were deemed invalid, HTTPS only. Metric: num_invalid_http_requests

Valid Internet HTTP Requests

Rate of incoming requests that were deemed valid, HTTP only. Metric: num_valid_http_requests

Invalid Internet HTTP Requests

Rate of incoming requests that were deemed invalid, HTTP only. Metric: num_invalid_http_requests

Prometheus: ACD dashboard

Logged Warnings

Rate of logged warnings since the router has started, divided into CDN-related and CDN-unrelated. Metric: num_log_warnings_total

Logged Errors

Rate of logged errors since the router has started. Metric: num_log_errors_total

HTTP Requests

Rate of responses sent to incoming connections. Metric: orc_latency_count

Number Of Active Sessions

Number of sessions opened on router that are still active. Metric: num_sessions

Total Number Of Sessions

Total number of sessions opened on router. Metric: num_sessions

Session Type Counts (Non-Stacked)

Number of active sessions divided by type; see metric documentation linked below for up-to-date list of types. Metric: num_sessions

Prometheus/ACD: Subrunners

Client Connections

Number of currently open client connections per subrunner. Metric: subrunner_client_conns

Asynchronous Queues (Current)

Number of queued events per subrunner, roughly corresponding to load. Metric: subrunner_async_queue

Used <Send/receive> Data Blocks

Number of send or receive data blocks currently in use per subrunner, as decided by the “Send/receive” drop down box. Metric: subrunner_used_send_data_blocks and subrunner_used_receive_data_blocks

Asynchronous Queues (Max)

Maximum number of events waiting in queue. Metric: subrunner_max_async_queue

Total <Send/receive> Data Blocks

Number of send or receive data blocks allocated per subrunner, as decided by the “Send/receive” drop down box. Metric: subrunner_total_send_data_blocks and subrunner_total_receive_data_blocks

Low Queue (Current)

Number of low priority events queued per subrunner. Metric: subrunner_low_queue

Medium Queue (Current)

Number of medium priority events queued per subrunner. Metric: subrunner_medium_queue

High Queue (Current)

Number of high priority events queued per subrunner. Metric: subrunner_high_queue

Low Queue (Max)

Maximum number of events waiting in low priority queue. Metric: subrunner_max_low_queue

Medium Queue (Max)

Maximum number of events waiting in medium priority queue. Metric: subrunner_max_medium_queue

High Queue (Max)

Maximum number of events waiting in high priority queue. Metric: subrunner_max_high_queue

Wakeups

The number of times a subrunner has been waken up from sleep. Metric: subrunner_io_wakeups

Overloaded

The number of times the number of queued events for a subrunner exceeded its maximum. Metric: subrunner_times_worker_overloaded

Autopause

Number of sockets that have been automatically paused. This happens when the work manager is under heavy load. Metric: subrunner_io_autopause_sockets

1.8.4 - Alarms and Alerting

Configuring alarms and alerting

Alerts are generated by the third-party service Prometheus, which sends them to the Alertmanager service. A default containerized instance of Alertmanager is deployed alongside ESB3024 Router. Out of the box, Alertmanager ships with only a sample configuration file, and will require manual configuration prior to enabling the alerting functionality. Due to the many different possible configurations for how alerts are both detected and where they are pushed, the official Alertmanager documentation should be followed for how to configure the service.

The router ships with Alertmanager 0.25, the documentation for which can be found at prometheus.io. The Alertmanager configuration file can be found on the host at /opt/edgeware/acd/alertmanager/alertmanager.yml.

Accessing Alertmanager

Alertmanager has a web interface that is listening for HTTP connections on port 9093. There is no authentication, so anyone who has access to the host that is running Alertmanager can access the interface.

Starting / Stopping Alertmanager

After the service is configured, it can be managed via systemd, under the service unit acd-alertmanager.

systemctl start acd-alertmanager

For EL7 systems running under Docker, the container must be started or stopped using the respective Docker start/stop commands. Note that the acd- prefix is not applicable under Docker.

docker start alertmanager

Logging

The container logs are automatically published to the system journal, under the same unit descriptor, and can be viewed using journalctl

journalctl -u acd-alertmanager

For EL7 systems running under Docker, the container logs can only be viewed using the docker logs command. Note that the acd- prefix is not applicable under Docker.

docker logs alertmanager

1.8.5 - Monitoring multiple routers

By default an instance of Prometheus only monitors the ESB3024 Router that is installed on the same host as where Prometheus is installed. It is possible to make it monitor other router instances and visualize all instances on one Grafana instance.

Configuring of Prometheus

This is configured in the scraping configuration of Prometheus, which is found in the file /opt/edgeware/acd/prometheus/prometheus.yaml, which typically looks like this:

global:
  scrape_interval:     15s

rule_files:
  - recording-rules.yaml

# A scrape configuration for router metrics
scrape_configs:
  - job_name: 'router-scraper'
    scheme: https
    tls_config:
      insecure_skip_verify: true
    static_configs:
    - targets:
      - acd-router-1:5001
    metrics_path: /m1/v1/metrics
    honor_timestamps: true
  - job_name: 'edns-proxy-scraper'
    scheme: http
    static_configs:
    - targets:
      - acd-router-1:8888
    metrics_path: /metrics
    honor_timestamps: true

More routers can be added to the scrape configuration by simply adding more routers under targets in the scraper jobs.

For instance, to monitor acd-router-2 and acd-router-3 along acd-router-1, the configuration file needs to be modified like this:

global:
  scrape_interval:     15s

rule_files:
  - recording-rules.yaml

# A scrape configuration for router metrics
scrape_configs:
  - job_name: 'router-scraper'
    scheme: https
    tls_config:
      insecure_skip_verify: true
    static_configs:
    - targets:
      - acd-router-1:5001
      - acd-router-2:5001
      - acd-router-3:5001
    metrics_path: /m1/v1/metrics
    honor_timestamps: true
  - job_name: 'edns-proxy-scraper'
    scheme: http
    static_configs:
    - targets:
      - acd-router-1:8888
      - acd-router-2:8888
      - acd-router-3:8888
    metrics_path: /metrics
    honor_timestamps: true

After the file has been modified, Prometheus needs to be restarted by typing

systemctl restart acd-prometheus

It is possible to use the same configuration on multiple routers, so that all routers in a deployment can monitor each other.

Selecting router in Grafana

In the top left corner the Grafana dashboards have a drop-down menu labeled “ACD Router”, which allows to choose which router to monitor.

1.8.6 - Routing Rule Evaluation Metrics

Node Visit counters

ESB3024 Router counts the number of times a node and any of its children is selected in the routing table.

The visit counters can be retrieved with the following end points:

/v1/node_visits

  • Returns visit counters for each node as a flat list of host:counter pairs in JSON.

  • Example output:

    {
      "node1": "1",
      "node2": "1",
      "node3": "1",
      "top": "3"
    }
    

/v1/node_visits_graph

  • Returns a full graph of nodes with their respective visit counters in GraphML.

  • Example output:

    <?xml version="1.0"?>
    <graphml xmlns="http://graphml.graphdrawing.org/xmlns"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns
    http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
      <key id="visits" for="node" attr.name="visits" attr.type="string" />
      <graph id="G" edgedefault="directed">
        <node id="routing_table">
          <data key="visits">5</data>
        </node>
        <node id="cdn1">
          <data key="visits">1</data>
        </node>
        <node id="node1">
          <data key="visits">1</data>
        </node>
        <node id="cdn2">
          <data key="visits">2</data>
        </node>
        <node id="node2">
          <data key="visits">2</data>
        </node>
        <node id="cdn3">
          <data key="visits">2</data>
        </node>
        <node id="node3">
          <data key="visits">2</data>
        </node>
        <edge id="e0" source="cdn1" target="node1" />
        <edge id="e1" source="routing_table" target="cdn1" />
        <edge id="e2" source="cdn2" target="node2" />
        <edge id="e3" source="routing_table" target="cdn2" />
        <edge id="e4" source="cdn3" target="node3" />
        <edge id="e5" source="routing_table" target="cdn3" />
      </graph>
    </graphml>
    
  • To receive the graph as JSON, specify Accept:application/json in the request headers.

  • Example output:

    {
      "edges": [
        {
          "source": "cdn1",
          "target": "node1"
        },
        {
          "source": "routing_table",
          "target": "cdn1"
        },
        {
          "source": "cdn2",
          "target": "node2"
        },
        {
          "source": "routing_table",
          "target": "cdn2"
        },
        {
          "source": "cdn3",
          "target": "node3"
        },
        {
          "source": "routing_table",
          "target": "cdn3"
        }
      ],
      "nodes": [
        {
          "id": "routing_table",
          "visits": "5"
        },
        {
          "id": "cdn1",
          "visits": "1"
        },
        {
          "id": "node1",
          "visits": "1"
        },
        {
          "id": "cdn2",
          "visits": "2"
        },
        {
          "id": "node2",
          "visits": "2"
        },
        {
          "id": "cdn3",
          "visits": "2"
        },
        {
          "id": "node3",
          "visits": "2"
        }
      ]
    }
    

Resetting Visit Counters

A node visit counter with an id not matching any node id of a newly applied routing table is destroyed.

Reset all counters to zero by momentarily applying a configuration with a placeholder routing root node, that has unique id and an empty members list, e.g:

"routing": {
  "id": "empty_routing_table",
  "members": []
}

… and immediately reapply the desired configuration.

1.8.7 - Metrics

Metrics endpoint

ESB3024 Router collects a large number of metrics that can give insight into it’s condition at runtime. Those metrics are available in Prometheustext-based exposition format at endpoint :5001/m1/v1/metrics.

Below is the description of these metrics along with their labels.

client_response_status

Number of responses sent back to incoming requests.

lua_num_errors

Number of errors encountered when evaluating Lua rules.

  • Type: counter

lua_num_evaluators

Number of Lua rules evaluators (active interpreters).

lua_time_spent

Time spent by running Lua evaluators, in microseconds.

  • Type: counter

num_configuration_changes

Number of times configuration has been changed since the router has started.

  • Type: counter

num_endpoint_requests

Number of requests redirected per CDN endpoint.

  • Type: counter
  • Labels:
    • endpoint - CDN endpoint address.
    • selector - whether the request was counted during initial or instream selection.

num_invalid_http_requests

Number of client requests that either use wrong method or wrong URL path. Also number of all requests that cannot be parsed as HTTP.

  • Type: counter
  • Labels:
    • source - name of internal filter function that classified request as invalid. Probably not of much use outside debugging.
    • type - whether the request was HTTP (Unencrypted) or HTTPS (SSL).

num_log_errors_total

Number of logged errors since the router has started.

  • Type: counter

num_log_warnings_total

Number of logged warnings since the router has started.

  • Type: counter

num_managed_redirects

Number of redirects to the router itself, which allows session management.

  • Type: counter

num_manifests

Number of cached manifests.

  • Type: gauge
  • Labels:
    • count - state of manifest in cache, can be either lru, evicted or total.

num_qoe_losses

Number of “lost” QoE decisions per CDN.

  • Type: counter
  • Labels:
    • cdn_id - ID of CDN that loose QoE battle.
    • cdn_name - name of CDN that loose QoE battle.
    • selector - whether the decision was taken during initial or instream selection.

num_qoe_wins

Number of “won” QoE decisions per CDN.

  • Type: counter
  • Labels:
    • cdn_id - ID of CDN that won QoE battle.
    • cdn_name - name of CDN that won QoE battle.
    • selector - whether the decision was taken during initial or instream selection.

num_rejected_requests

Deprecated, should always be at 0.

  • Type: counter
  • Labels:
    • selector - whether the request was counted during initial or instream selection.

num_requests

Total number of requests received by the router.

  • Type: counter
  • Labels:
    • selector - whether the request was counted during initial or instream selection.

num_sessions

Number of sessions opened on router.

  • Type: gauge
  • Labels:
    • state - either active or inactive.
    • type - one of: initial, instream, qoe_on, qoe_off, qoe_agent or sp_agent.

num_ssl_errors_total

Number of all errors logged during TLS connections, both incoming and outgoing.

  • Type: counter

num_ssl_warnings_total

Number of all warnings logged during TLS connections, both incoming and outgoing.

  • Type: counter
  • Labels:
    • category - which kind of TLS connection triggered the warning. Can be one of: cdn, content, generic, repeated_session or empty.

num_unhandled_requests

Number of requests for which no CDN could be found.

  • Type: counter
  • Labels:
    • selector - whether the request was counted during initial or instream selection.

num_unmanaged_redirects

Number of redirects to “outside” the router - usually to CDN.

  • Type: counter
  • Labels:
    • cdn_id - ID of CDN picked for redirection.
    • cdn_name - name of CDN picked for redirection.
    • selector - whether the redirect was result of initial or instream selection.

num_valid_http_requests

Number of received requests that were not deemed invalid, see num_invalid_http_requests.

  • Type: counter
  • Labels:
    • source - name of internal filter function that classified request as invalid. Probably not of much use outside debugging.
    • type - whether the request was HTTP (Unencrypted) or HTTPS (SSL).

orc_latency_bucket

Total number of responses sorted into “latency buckets” - labels denoting latency interval.

  • Type: counter
  • Labels:
    • le - latency bucket that given response falls into.
    • orc_status_code - HTTP status code of given response.

orc_latency_count

Total number of responses.

  • Type: counter
  • Labels:
    • tls - whether the response was sent via SSL/TLS connection or not.
    • orc_status_code - HTTP status code of given response.

ssl_certificate_days_remaining

Number of days until a SSL certificate expires.

  • Type: gauge
  • Labels:
    • domain - the common name of the domain that the certificate authenticates.
    • not_valid_after - the expiry time of the certificate.
    • not_valid_before - when the certificate starts being valid.
    • usable - if the certificate is usable to the router, see the ssl_certificate_usable_count metric for an explanation.

ssl_certificate_usable_count

Number of usable SSL certificates. A certificate is usable if it is valid and authenticates a domain name that points to the router.

  • Type: gauge

1.8.7.1 - Internal Metrics

Internal Metrics

A subrunner is an internal module of ESB3024 Router which handles routing requests. The subrunner metrics are technical and mainly of interest for Agile Content. These metrics will be briefly described here.

subrunner_async_queue

Number of queued events per subrunner, roughly corresponding to load.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_client_conns

Number of currently open client connections per subrunner.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_high_queue

Number of high priority events queued per subrunner.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_io_autopause_sockets

Number of sockets that have been automatically paused. This happens when the work manager is under heavy load.

  • Type: counter
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_io_send_data_fast_attempts

A fast data path was added that in many cases increases the performance of the router. This metric was added to verify that the fast data path is taken.

  • Type: counter
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_io_wakeups

The number of times a subrunner has been waken up from sleep.

  • Type: counter
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_low_queue

Number of low priority events queued per subrunner.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_max_async_queue

Maximum number of events waiting in queue.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_max_high_queue

Maximum number of events waiting in high priority queue.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_max_low_queue

Maximum number of events waiting in low priority queue.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_max_medium_queue

Maximum number of events waiting in medium priority queue.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_medium_queue

Number of medium priority events queued per subrunner.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_times_worker_overloaded

Number of times when queued events for given subrunner exceeded the tuning.overload_threshold value (defaults to 32).

  • Type: counter
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_total_receive_data_blocks

Number of receive data blocks allocated per subrunner.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_total_send_data_blocks

Number of send data blocks allocated per subrunner.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_used_receive_data_blocks

Number of receive data blocks currently in use per subrunner. Same as subrunner_total_receive_data_blocks.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

subrunner_used_send_data_blocks

Number of send data blocks currently in use per subrunner. Same as subrunner_total_send_data_blocks.

  • Type: gauge
  • Labels:
    • subrunner_id - ID of given subrunner.

1.9 - Releases

ESB3024 Router releases

1.9.1 - Release esb3024-1.10.2

Build date

2024-06-03

Release status

Type: production

Breaking changes

If upgrading from a release prior to 1.10.0, the configuration needs to be manually updated after upgrading to 1.10.2. See Installing release 1.10.x for more information.

Change log

  • FIXED: ConsistentHashing rule broken [ESB3024-969]
  • FIXED: Increase configuration size limit [ESB3024-983]

Known Limitations

None

1.9.2 - Release esb3024-1.10.1

Build date

2024-04-18

Release status

Type: production

Breaking changes

If upgrading from a release prior to 1.10.0, the configuration needs to be manually updated after upgrading to 1.10.1. See Installing release 1.10.x for more information.

Change log

  • NEW: Change predictive load balancing functions to use megabits/s [ESB3024-932]
  • FIXED: Logic classifier statements can consume all memory [ESB3024-937]

Known Limitations

None

1.9.3 - Release esb3024-1.10.0

Build date

2024-04-02

Release status

Type: production

Breaking changes

The configuration needs to be manually updated after upgrading to 1.10.0. See Installing release 1.10.0 for more information.

Change log

  • NEW: Use metrics from streamers in routing decisions. Added standard library Lua support to use hardware metrics in routing decisions. Added host health checks in the configuration. [ESB3024-154]
  • NEW: Remove unused field “apiKey” from configuration [ESB3024-426]
  • NEW: Support integration with Convoy Analytics [ESB3024-694]
  • NEW: Support combining classifiers using AND/OR in session groups [ESB3024-776]
  • NEW: Enable access logging by default [ESB3024-816]
  • NEW: Improved Lua translation function error handling [ESB3024-874]
  • NEW: Updated predictive load balancing functions to support hardware metrics [ESB3024-887]
  • NEW: Remove apiKey from documentation [ESB3024-927]
  • FIXED: Condition with ‘or’ statement sometimes generate faulty Lua [ESB3024-863]

Known Limitations

None

1.9.4 - Release esb3024-1.8.0

Build date

2024-02-07

Release status

Type: production

Breaking changes

The configuration needs to be manually updated after upgrading to 1.8.0. See Installing release 1.8.0 for more information.

Change log

  • NEW: Remove ESB3026 Account Monitor from installer. [ESB3024-354]
  • NEW: Improve selection input endpoint flexibility and security. See API overview documentation for details. [ESB3024-423]
  • NEW: Support anonymous geoip rules [ESB3024-699]
  • NEW: Add ASN IDs list classifiers to confd [ESB3024-778]
  • NEW: Enable content popularity tracking by default. Added option to enable/disable in confd/confcli. [ESB3024-781]
  • NEW: Remove dependency on session from security token verification [ESB3024-809]
  • FIXED: A lot of JSON output on failed routing. HTTP response no longer contains internal routing information. [ESB3024-523]
  • FIXED: Returning Lua table from Lua debug endpoint can crash router. Selection Input values now support floating point values in a Lua context [ESB3024-691]
  • FIXED: Floating point selection inputs are truncated to ints when passed to Lua context [ESB3024-710]
  • FIXED: Race condition between RestApi and Session [ESB3024-753]
  • FIXED: confd/concli doesn’t support “forward_host_header” on hostGroups [ESB3024-761]
  • FIXED: Support Lua vector keys in reverse order [ESB3024-780]

Known Limitations

None

1.9.5 - Release esb3024-1.6.0

Build date

2023-12-20

Release status

Type: production

Breaking changes

The configuration needs to be manually updated after upgrading to 1.6.0. See configuration changes between 1.4.0 and 1.6.0 for more information.

Change log

  • NEW: Remove the lua_paths array from the config . Lua scripts are now added using a REST API on the /v1/lua/ endpoint. [ESB3024-204]
  • NEW: Separate “account-monitor” from installer [ESB3024-238]
  • NEW: Consistent hashing based routing . Added support for content distribution control for load balancing and cache partitioning [ESB3024-274]
  • NEW: Predictive load balancing . Account for in-transit traffic to prevent cache overload when there is a sudden burst of new sessions. [ESB3024-275]
  • NEW: Support Convoy security tokens [ESB3024-386]
  • NEW: Expose quality, host and session ID in the session object in Lua context [ESB3024-429]
  • NEW: Support upgrade of system python in installer [ESB3024-442]
  • NEW: Do not configure selinux and firewalld in installer [ESB3024-493]
  • NEW: Convoy Distribution/Account integration [ESB3024-503]
  • NEW: Make eDNS server port configurable . The router configuration hosts.proxy_address has been renamed to hosts.proxy_url and now accepts a port that is used when connecting to the proxy. The cdns.http_port and cdns.https_port configurations now configure the port that is used for connecting to the EDNS server, before they configured the port that was used for connecting to the proxy. [ESB3024-509]
  • NEW: Expand node table in Lua context . New fields are: node.id, node.visits, host.id, host.recent_selections [ESB3024-630]
  • FIXED: DNS lookup can fail . DNS lookup can fail when same content requested from both IPv4 and IPv6 clients [ESB3024-427]
  • FIXED: Failed DNS requests are not retried . Fixed bug where failed eDNS requests were not retried [ESB3024-504]
  • FIXED: Lua functions are not updated when uploaded [ESB3024-544]
  • FIXED: Undefined metatable fields evaluate to false rather than nil [ESB3024-642]
  • FIXED: Evaluator::evaluate() doesn’t support different types of its variadic arguments [ESB3024-687]
  • FIXED: Segfault when accessing REST api with empty path [ESB3024-752]
  • FIXED: Container UID/GID may change between versions [ESB3024-755]

1.9.6 - Release esb3024-1.4.0

Build date

2023-09-29

Release status

Type: production

Breaking changes

  • All configuration is now stored under /opt/edgeware/acd, see [ESB3024-425]. Any configuration that is to be kept needs to be manually migrated.
    Typically /opt/edgeware/etc/confd/store/store.json needs to be copied to /opt/edgeware/acd/confd/store/store.json, /opt/edgeware/var/lib/acd-router/cached-acd-router-config.json needs to be copied to /opt/edgeware/acd/router/cache/config.json and /opt/edgeware/var/lib/acd-router/cached-router-rest-api-key.json needs to be copied to /opt/edgeware/acd/router/cache/rest-api-key.json. Custom Lua functions need to be migrated from /opt/edgeware/acd/var/lib/custom_lua to /opt/edgeware/acd/router/lib/custom_lua. The Prometheus and Grafana configurations also need to be copied if they have been modified.

    The following changes were made to the confcli configuration [ESB3024-455].
  • The rule fields inside the routing rule items were renamed to condition to avoid confusion with the rules list. This applies to the blocks allow, deny, split and weighted.
  • The popularityThreshold in the contentPopularity routing rule was renamed to contentPopularityCutoff.

Change log

  • NEW: 1-Page Status Report . Added command ew-sysinfo that can be used on any machine with an ESB3024 installation. The command outputs various information about the system and installed services which can be used for monitoring and diagnostics. [ESB3024-391]
  • NEW: Update routing rule property names . Routing rule property names updated for consistency and clarity [ESB3024-455]
  • FIXED: Deleting confd API array element inside oneOf object fails [ESB3024-355]
  • FIXED: Container logging not captured by systemd until services are restarted [ESB3024-359]
  • FIXED: Alertmanager restricts the configuration to a single file [ESB3024-381]
  • FIXED: Split rules in routing configuration should terminate on error [ESB3024-420]
  • FIXED: Improve alert configuration in Prometheus [ESB3024-422]
  • FIXED: Inconsistent storage paths of service configuration and data [ESB3024-425]
  • FIXED: confd-transformer is not working in el7 [ESB3024-430]

1.9.7 - Release acd-router-1.2.3

Build date

2023-08-16

Release status

Type: production

Breaking changes

None

Change log

  • NEW: Add more classifiers . New classifiers are hostName, contentUrlPath, userAgent, contentUrlQueryParameters [ESB3024-298]
  • NEW: Add allow- and denylist rule blocks [ESB3024-380]
  • NEW: Add enhanced validation of scriptable field in routing rules [ESB3024-393]
  • NEW: Add services to the config tree [ESB3024-410]
  • NEW: Prohibit unknown configuration properties [ESB3024-416]
  • FIXED: Duplicate session group IDs are allowed [ESB3024-49]
  • FIXED: Invalid URL returned for IPv4 requests when using a DNS backend [ESB3024-374]
  • FIXED: Not possible to set log level in eDNS proxy [ESB3024-378]
  • FIXED: Instream selection fails when DASH manifest has template paths using “../” [ESB3024-384]

1.9.8 - Release acd-router-1.2.0

Build date

2023-06-27

Release status

Type: production

Breaking changes

None

Change log

  • NEW: Add meta fields to the configuration . The API now allows the meta data fields “created_at”, “source” and “source_checksum” that can be used for the API consumer to track who did what change when.
  • NEW: Control routing behavior based on backend response code . This gives control over when to return backend response codes to the end user and when to trigger a failover to another CDN or host.
  • NEW: Manage Lua scripts via API
  • NEW: Support popularity-based routing . Content can be ordered in multiple groups with descending popularity. Popularity can also be tracked per session group.
  • NEW: Improved support for IPv6 routing . It is now possible to select backend depending on the IP protocol version.
  • NEW: Add DNS backend support . This allows delegating routing decisions to an EDNS0 server.
  • NEW: Support HMAC with SHA256 in Lua scripts
  • NEW: Add alarm support . The alarms are handled by Prometheus and Alertmanager.
  • NEW: Support saving Grafana Dashboards
  • NEW: Add simplified configuration API and CLI tool . A new configuration API with an easier to use model has been added. The “confcli” tool present in many other Edgeware products is now supported.
  • NEW: Add authentication to the REST API
  • FIXED: Host headers not forwarded to Request Router when ‘redirecting: true’ is enabled
  • FIXED: IP range classifier 0.0.0.0/0 does not work in session groups

1.9.9 - Release acd-router-1.0.0

First production

Build date

2022-11-22

Release status

Type: First production release

Known Limitations

The setting “allowed_clients” should not be used since the functionality does not work as expected.

Change log

  • Flexible routing rule engine with support for Lua plugins. Support many use cases, including CDN Offload and CDN Selection.
  • Advanced client classification mechanisms for routing based on group memberships (device type, content type, etc).
  • Geobased routing including dedicated high-performing API for subnet matching, associating an incoming request with a region.
  • Integration API to feed the service with arbitrary variables to use for routing decisions. Can be used to get streaming bitrate in public CDNs, status from network probes, etc.
  • Flexible request/response translation manipulation on the client facing interface. Can be used for URL manipulation, encoding/decoding tokens or adapting the interface to e.g. the PowerDNS backend protocol.
  • Metrics API that can be monitored with standard monitoring software. Out-of-the-box integration with Prometheus and Grafana.
  • Robust deployment with each service instance running independently, and allowing the service to stay in operational state even when backends become temporarily unavailable.
  • RHEL 7/8 support.
  • Online documentation at https://docs.agilecontent.com/

1.10 - Glossary

ESB3024 Router definitions of commonly used terms
ACD
Agile CDN Director. See “Director”.
Confd
A backend service that hosts the service configuration. Comes with an API, a CLI and a GUI.
Classifier
A filter that associate a request with a tag that can be used to define session groups.
Director
The Agile Delivery OTT router and related services.
ESB
A software bundle that can be separately installed and upgraded, and is released as one entity with one change log. Each ESB is identified with a number. Over time, features and functions within an ESB can change.
Lua
A widely available scripting language that is often used to extend the capabilities of a piece of software.
Router
Unless otherwise specified, an HTTP router that manages an OTT session using HTTP redirect. There are also ways to use DNS instead of HTTP.
Selection Input API
Data posted to this API can be accessed by the routing rules and hence influence the routing decisions.
Subnet API
An API to define mappings between subnets and names (typically regions) for those subnets. Routing rules can then refer to the names rather than the subnets.
Session Group
A handle on a group of requests, defined via classifiers.

2 - ESB3032 ACD Aggregator

Aggregates CDN statistics

2.1 - Getting Started

Getting started with the Account Aggregator

The account aggregator is a service responsible for monitoring various input streams, compiling and aggregating statistics, and selectively reporting to one or more output streams. It acts primarily as a centralized collector of metrics which may have various aggregations applied before being published to one or more endpoints.

Modes of operation

There are two primary modes of operation, a live-monitoring mode, as well as a reporting mode. The live-monitoring mode measures the account records in real-time, filters, and aggregates the data to the various outputs in real-time. In this mode, only the most recent data will be considered, and any historical context upon startup may be skipped. In the reporting mode, the account record data will be consumed and processed in the order in which they were published to Kafka, and the service will guarantee that all records, still available within the Kafka topic will be processed and reported upon.

Activating the various modes of operation is performed by way of the set of input and output blocks within the configuration file. The file may contain one or more input blocks which specify where the data is sourced, e.g. account records from Kafka, and one or more output blocks which determine how and where the aggregated statistics are published.

While it is possible to specify multiple input and output blocks within a single configuration file, it is highly recommended to separate each pairing of input and output blocks into separate instances running on different nodes. This will yield the best performance and provide for better load balancing, since each instance will be responsible for a single mode of operation.

Real-time account monitoring

In the real-time account monitoring mode, account records, which are sent from each streaming server through the Kafka message broker, are processed by the account aggregator, and current real-time throughput metrics are updated in a Redis database. These metrics, which are constantly being updated, reflect the most current state of the CDN, and can be used by the Convoy Request Router to make real-time routing decisions.

PCX Reporting

In the PCX collector mode, account records are consumed in such a way that past throughput and session statistics can be aggregated to produce billing related reports. These reports are not considered real-time metrics, but represent usage statistics over fixed time intervals. This mode of operation requires a PCX API compatible reporting endpoint. See Appendix B for additional information regarding the PCX reporting format.

Installation

Prerequisites

The account aggregator is shipped as a compressed OCI formatted container image and as such, it requires a supported container runtime such as one of the following:

  • Docker
  • Podman
  • Kubernetes

Any runtime capable of running a Linux container should work the same. For simplicity, the following installation instructions assume that Docker is being used, and that Docker is already configured and running on the target system.

To test that Docker is setup and running, and that the current user has the required privileges to create a container, you may execute the following command.

$ docker run hello-world

Hello from Docker!
This message shows that your installation appears to be working correctly.

To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
    (amd64)
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.

To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash

Share images, automate workflows, and more with a free Docker ID:
 https://hub.docker.com/

For more examples and ideas, visit:
 https://docs.docker.com/get-started/

If you get a permission denied error, ensure that the current user is a member of the docker group or execute all Docker commands under sudo.

Loading the container image

The container image is delivered as a compressed OCI formatted image, which can be loaded directly via the docker load command. The following assumes that the image is in /tmp/esb3032-acd-aggregator-0.0.0.gz

docker load --input /tmp/esb3032-acd-aggregator-0.0.0.gz

You will now be able to verify that the image was loaded successfully by executing the following and looking for the image name in the output.

$ docker images | grep acd-aggregator

images.edgeware.tv/esb3032-acd-aggregator latest   4bbe28b444d3 1 day ago  2.08GB

Creating the configuration file

The configuration file may be located anywhere on the filesystem, however it is recommended to keep everything under the /opt/edgeware/acd/aggregator folder to be consistent with other products under the ACD product family. If that folder doesn’t already exist, you may create the folder with the following command.

mkdir -p /opt/edgeware/acd/aggregator

If using a different location, you will need to map the folder to the container while creating the Docker container. Additional information describing how to map the volume is available in the section “Creating and starting the container” below.

The configuration file for the account aggregator is divided into several sections, input, output and tuning. One or more input blocks may be specified to configure from where the data should be sourced. One or more output blocks may be configured which determine to where the resulting aggregated data is published. Finally the tuning block configures various global settings for how the account aggregator operates, such as the global log_level.

Configuring the input source

As of the current version of the account aggregator, there is only a single type of input source supported, and that is account_records. This input source connects to a Kafka message broker, and consumes account records.
Depending on which output types are configured, the Kafka consumer may either start by processing the oldest or most recent records first.

The following configuration block sample will be used as an example in the description below.

Note that the key input is surrounded by double-square-brackets. This is a syntax element to indicate that there may be multiple input sections in the configuration.

[[input]]
type = "account_records"
servers = [
    "kafka://192.0.2.1:9092",
    "kafka://192.0.2.2:9092",
]
group_name = "acd-aggregator"
kafka_max_poll_interval_ms = 30000
kafka_session_timeout_ms = 3000
log_level = "off"

The type property is used to determine the type of input, and the only valid value is account_records.

The servers list must contain at least 1 Kafka URL, prefixed with the URL scheme kafka://. If not specified, the default Kafka port of 9092 will be used. It is recommended but not required to specify all servers here, as the Kafka client library will obtain the full list of endpoints from the server on startup, however, the initial connection will be made to one or more of the provided URLs.

The group_name property identifies to which consumer group the aggregator should belong. Due to the type of data which account records represent, each instance of the aggregator connecting to the same Kafka message broker MUST have a unique group name. If two instances belong to the same group, the data will be partitioned among both instances, and the resulting aggregations may not be correct. If only a single instance of the account aggregator is used, this property is optional and defaults to “acd-aggregator”.

The kafka_* properties, for max_poll_interval and session_timeout are used to tune the connection parameters for the internal Kafka consumer. More details for these properties can be found in the documentation for the rdkafka library. See Kafka documentation for more details.

The log_level property configures the logging level for the Kafka library and supports the values “off”, “trace”, “debug”, “info”, “warn”, and “error”. By default, logging from this library is disabled. This should only be enabled for troubleshooting purposes, as it is extremely verbose, and any warnings or error messages will be repeated in the account aggregator’s log. The logging level for the Kafka library must be higher then the general logging level for the aggregator, as defined in the “tuning” section or the lower-level messages from the Kafka library will be skipped.

Configuring output

The account aggregator currently supports two types of output blocks, depending on the desired mode of operation. For reference purposes, both types will be described within this section, but it is recommended to only use a single type per instance of the account aggregator.

Note that the key output is surrounded by double-square-brackets. This is a syntax element to indicate that there may be multiple output sections in the configuration.

[[output]]
type = "account_monitor"
redis_servers = [
    "redis://192.0.2.7:6379/0",
    "redis://:password@192.0.2.8:6379/1",
]
stale_threshold_s = 12
throughput_correction_mbps = 0
minimum_check_interval_ms = 1000

[[output]]
type = "pcx_collector"
report_url = "https://192.0.2.5:8000/v1/collector"
client_id = "edgeware"
secret = "abc123"
report_timeout_ms = 2000
report_interval_s = 30
report_delay_s = 30
Real-time account monitor output

The first output block has the type account_monitor and represents the live account monitoring functionality, which publishes per-account bandwidth metrics to one or more Redis servers. When this type of output block is configured, the account records will be consumed starting with the most recent messages first, and offsets will not be committed. Stopping or restarting the service may cause account records to be skipped. This type of output is suitable for making real-time routing decisions, but should not be relied upon for critical billing or reporting metrics.

The redis_servers list consists of URLs to Redis instances which shall be updated with the current real-time bandwidth metrics. If the Redis instance requires authentication, the global instance password can be specified as part of the URL as in the second entry in the list. Since Redis does not support usernames, anything before the : in the credentials part of the URL will be ignored. At least 1 Redis URL must be provided.

The stale_threshold_s property determines the maximum timeout in seconds, after which, if no account records have been received for a given host, the host will be considered stale and removed.

The throughput_correction_mbps property can be used to add or subtract a fixed correction factor to the bandwidth reported in Redis. This is specified in megabits per second, and this may be either positive or negative. If the value is negative, and the calculated bandwidth is less than the correction factor, a minimum bandwidth of 0 will be reported.

The minimum_check_interval_ms property is used to throttle how frequently the statistics will be processed. By default, the account aggregator will not recalculate the statistics more than once per second. Setting this value too low will result in potentially higher CPU usage, while setting it too high may result in some account records being missed. The default of 1 second should be adequate for most situations.

PCX Collector output

The pcx_collector type configures the account aggregator as a reporting

agent for the PCX API. Whenever this configuration is present, the account record consumer will be configured to always start at the oldest records retained within the Kafka topic. It then processes the records one at a time, committing the Kafka offset each time a report is successfully received. This mode does not make any guarantees as to how recent the data is on which the reports are made, but does guarantee that every record will be counted in the aggregated report. Stopping or restarting the service will result in the account record consumer resuming processing from the last successful report. This type of reporting is suitable for billing purposes assuming that there are multiple replicated Kafka nodes, and that the service is not stopped for longer than the maximum retention period configured within Kafka. Stopping the service for longer than the retention period will result in messages being unavailable. Because this type of output requires that the Kafka consumer is processed in a specific order, and will not proceed with reading additional messages until all reports have been successfully received, it is not recommended to have both pcx_collector and the account_monitor type output blocks configured within the same instance.

The report_url property is a single HTTP endpoint URL where the PCX API can be reached. This property is required and may be either an HTTP or HTTPS URL. For HTTPS, the validity of the TLS certificate will be enforced, meaning that self-signed certificates will not be considered valid.

The client_id and secret fields are used to authenticate the client with the PCX API via token-based authentication. These fields are both required, however if not used by the specific PCX API instance, the empty string "" may be provided.

The report_timeout_ms field is an optional maximum timeout for the HTTP connection to the PCX API before the connection will fail. Failed reports will be retried indefinitely.

The report_interval_s property represents the interval bucket size for reporting metrics. The timing for this type of output is based solely on the embedded timestamp value of the account records, meaning that this property is not an absolute period on which the reports will be sent, but instead represents the duration between the start and ending timestamps of the report. Especially upon startup, reports may be sent much more frequently than this interval, but will always cover this duration of time.

The report_delay_s property is an optional offset used to account for both clock synchronization between servers as well as propagation delay of the account records through the message broker. The default delay is 30 seconds. This means that the ending timestamp of a given report will be no more recent than this many seconds in the past. It is important to include this delay, as any account records received with a timestamp that would be within period which has already been reported upon, will be dropped.

Tuning the account aggregator

The tuning configuration block represents the global properties for tuning how the account aggregator functions. Currently only one tuning property can be configured, and that is the log_level. The default log_level is “info”, which should be used in normal operation of the account aggregator, however, other possible values in order of verbosity include “trace”, “debug”, “info”, “warn”, “error”, and “off”.

Note that the tuning key is surrounded by single square-brackets. This is TOML syntax meaning that only one instance of tuning is allowed.

[tuning]
log_level = "info"

Example configurations

This section describes some example configuration files which can be used as a starting template depending on which mode of operation is desired.

Real-time account monitoring

This configuration will consume account records from a Kafka server running on 3 hosts, kafka-1, kafka-2, and kafka-3. The account records will be consumed starting with the most recent records. The resulting aggregations will be published to two Redis instances, running on redis-1 and redis-2. The reported bandwidth will have a 2Gb/s correction factor applied.

[[input]]
type = "account_records"
servers = [
    "kafka://kafka-1:9092",
    "kafka://kafka-2:9092",
    "kafka://kafka-3:9092"
]
group_name = "acd-aggregator-live"
# kafka_max_poll_interval_ms = 30000
# kafka_session_timeout_ms = 3000
# log_level = "off"

[[output]]
type = "account_monitor"
redis_servers = [
    "redis://redis-1:6379/0",
    "redis://redis-2:6379/0",
]
# stale_threshold_s = 12
throughput_correction_mbps = 2000
# minimum_check_interval_ms = 1000

[tuning]
log_level = "info"

The keys prefixed by # are commented out, since the default values will be used. They are included in the example for completeness.

PCX collector

This configuration will consume account records starting from the earliest record, calculate aggregated statistics for every 30 seconds, offset with a delay of 30 seconds, and publish the results to https://pcx.example.com/v1/collector.

[[input]]
type = "account_records"
servers = [
    "kafka://kafka-1:9092",
    "kafka://kafka-2:9092",
    "kafka://kafka-3:9092"
]
group_name = "acd-aggregator-pcx"
# kafka_max_poll_interval_ms = 30000
# kafka_session_timeout_ms = 3000
# log_level = "off"

[[output]]
type = "pcx_collector"
report_url = "https://pcx.example.com/v1/collector"
client_id = "edgeware"
secret = "abc123"
# report_timeout_ms = 2000
# report_interval_s = 30
# report_delay_s = 30

[tuning]
log_level = "info"

The keys prefixed by # are commented out, since the default values will be used. They are included in the example for completeness.

Combined PCX collector with real-time account monitoring

While this configuration is possible, it is not recommended, since the pcx_collector output type will force all records to be consumed starting at the earliest record. This will cause the live statistics to be delayed until ALL earlier records have been consumed, and reports have been successfully accepted by the PCX API. This combined role configuration can be used to minimize the number of servers or services running if the above limitations are acceptable.

Note: This is simply the combination of the above two output blocks in the same configuration file.

[[input]]
type = "account_records"
servers = [
    "kafka://kafka-1:9092",
    "kafka://kafka-2:9092",
    "kafka://kafka-3:9092"
]
group_name = "acd-aggregator-combined"
# kafka_max_poll_interval_ms = 30000
# kafka_session_timeout_ms = 3000
# log_level = "off"

[[output]]
type = "account_monitor"
redis_servers = [
    "redis://redis-1:6379/0",
    "redis://redis-2:6379/0",
]
# stale_threshold_s = 12
throughput_correction_mbps = 2000
# minimum_check_interval_ms = 1000

[[output]]
type = "pcx_collector"
report_url = "https://pcx.example.com/v1/collector"
client_id = "edgeware"
secret = "abc123"
# report_timeout_ms = 2000
# report_interval_s = 30
# report_delay_s = 30

[tuning]
log_level = "info"

Upgrading

The upgrade procedure for the aggregator consists of simply stopping the existing container with docker stop acd-aggregator, removing the existing container with docker rm acd-aggregator, and following the steps in “Creating and starting the container” below with the upgraded Docker image.

To roll back to a previous version, simply perform the same steps with the previous image. It is recommended to keep at least one previous image around until such time that you are satisfied with the new version. After which, you may remove the previous image with docker rmi images.edgeware.tv/esb3032-acd-aggregator:1.2.3 where “1.2.3” represents the previous version number.

Creating and starting the container

Now that the configuration file has been created, and the image has been loaded, we will need to create and start the container instance. The following docker run command will create a new container called “acd-aggregator”, start the process, and automatically resume the container once the Docker daemon is loaded at startup.

docker run \
  --name "acd-aggregator" \
  --detach \
  --restart=always \
  -v <PATH_TO_CONFIG_FOLDER>:/opt/edgeware/acd/aggregator:ro \
  <IMAGE NAME>:<VERSION> \
  --config /opt/edgeware/acd/aggregator/aggregator.toml

As an example using version 1.4.0:

docker run \
  --name "acd-aggregator" \
  --detach \
  --restart=always \
  -v /opt/edgeware/acd/aggregator:/opt/edgeware/acd/aggregator:ro \
  images.edgeware.tv/esb3032-acd-aggregator:1.4.0 \
  --config /opt/edgeware/acd/aggregator/aggregator.toml

Note: The image tag in the example is “1.4.0”, you will need to replace that tag with the image tag loaded from the compressed OCI formatted image file, which can be obtained by running docker images and searching for the account aggregator image as described in the step “Loading the container image” above.

If the configuration file saved in the previous step was at a different location from /opt/edgeware/acd/aggregator/aggregator.toml you will need to change both the -v option and the --config option in the above command to represent that location. The -v option mounts the containing folder from the host system on the left to the corresponding path inside the container on the right, and the :ro tells Docker that the volume is mounted read-only. The --config should be the absolute path to the configuration file from INSIDE the container. For example, if you saved the configuration file as /host/path/config.toml on the host, and you need to map that to /container/path/config.toml within the container, the lines should be -v /host/path:/container/path:ro and --config /container/path/config.toml respectively.

The --restart=always line tells Docker to automatically restart the container when the Docker runtime is loaded, and is the equivalent in systemd to “enabling” the service.

Starting and Stopping the container

To view the status of the running container, use the docker ps command. This will give a line of output for the acd-aggregator container if it is currently running. Appending the -a flag, will list the aggregator container if is not running as well.

Execute the following:

docker ps -a

You should see a line for the container with the container name “acd-aggregator” along with the current state of the container. If all is OK, you should see the container process running at this point, but it may show as “exited” if there was a problem.

To start and stop the container the docker start acd-aggregator and docker stop acd-aggregator commands can be used.

Viewing the logs

By default, Docker will maintain the logs of the individual containers within its own internal logging subsystem, which requires the user to use the command

docker logs

to view them. It is possible however to configure the Docker daemon to send logs to the system journal, however configuring that is beyond the scope of this document. Additional details describing how to do that are described here

[https://docs.docker.com/config/containers/logging/journald/].

To view the complete log for the aggregator the following command can be used.

docker logs acd-aggregator

Supplying the -f flag, can be used to “follow” the log until either the process terminates or CTRL+C is pressed.

docker logs -f acd-aggregator

Appendix A: Real-time account monitoring

Redis key value pairs

Each account will have a single key-value stored in Redis with the current throughput with any correction factor applied, which will be updated in real-time every time all hosts for the given account have received a new account record. This should be approximately every 10 seconds, but may vary slightly due to processing time.

The keys are structured in the following format:

bandwidth:<account>:value

and the value is reported in bits-per-second.

For example for accounts foo, bar and baz we may see the following:

bandwidth:foo:value = 123456789
bandwidth:bar:value = 234567890
bandwidth:baz:value = 102400

These values represent the most current throughput for each account, and will be updated periodically. A TTL of 48 hours is added to the keys, such that they will be pruned automatically after 48 hours since the last update. This is to prevent stale keys from remaining in Redis indefinitely. This TTL is not configurable by the end user.

Appendix B: PCX collector reporting

PCX reporting format

The following is an example of the report sent to the PCX HTTP endpoint.

{
    timestamp_begin: 1674165540,
    timestamp_end: 1674165570,
    writer_id: "writer-1",
    traffic: [
        Traffic {
            account_id: "unknown",
            num_ongoing_sessions: 0,
            bytes_transmitted: 0,
            edges: [
                Edge {
                    server: "orbit-1632",
                    num_ongoing_sessions: 0,
                    bytes_transmitted: 0,
                },
            ],
        },
        Traffic {
            account_id: "default",
            num_ongoing_sessions: 747,
            bytes_transmitted: 75326,
            edges: [
                Edge {
                    server: "orbit-1632",
                    num_ongoing_sessions: 747,
                    bytes_transmitted: 75326,
                },
            ],
        },
    ],
}

The report can be broken down into 3 parts. The outer root section includes the starting and stopping timestamps, as well as a writer_id field which is currently unused. For each account a Traffic section contains the aggregated statistics for that account, as well as a detailed breakdown of each Edge. An Edge is the portion of traffic for the account streamed by each server. Within an Edge the num_ongoing_sessions represents the peak ongoing sessions during the reporting interval, while the bytes_transmitted represents the total egress bandwidth in bytes over the entire period. For each outer Traffic section, the num_ongoing_sessions and bytes_transmitted represent the sum of the corresponding entries in all Edges.

Data protection and consistency

The ACD aggregator works by consuming messages from Kafka. Once a report has successfully been submitted, as determined by a 200 OK HTTP status from the reporting endpoint, the position in the Kafka topic will be committed. This means that if the aggregator process stops and is restarted, reporting will resume from the last successful report, and no data will be lost. There is a limitation to this, however, and that has to do with the data retention time of the messages in Kafka and the TTL value specified in the aggregator configuration. Both default to the same value of 24 hours. This means that if the aggregator process is stopped for more than 24 hours, data loss will result since the source account records will have expired from Kafka before they can be reported on by the aggregator.

Upon startup of the aggregator, all records stored in Kafka will be reported on in the order they are read, starting from either the last successful report or the oldest record currently in Kafka. Reports will be sent each time the timestamp in the current record read from Kafka exceeds the reporting interval meaning a large burst of reports will be sent at startup to cover each interval. Once the aggregator has caught up with the backlog of account records, it will send a single report roughly every 30 seconds (configurable).

It is not recommended to have more than a single account aggregator instance reading from Kafka at a time, as this will result in partial reports being sent to the HTTP endpoint which will require the endpoint to reconstruct the data upon receipt. All redundancy in the account aggregator is handled by the redundancy within Kafka itself. With this in mind, it is important to ensure that there are multiple Kafka instances running and that the aggregator is configured to read from all of them.

2.2 - Releases

ESB3032 ACD Aggregator releases

2.2.1 - Release esb3032-0.2.0

Build date

2022-12-21

Release status

Type: devdrop

Change log

  • NEW: Use config file instead of command line switches
  • NEW: Reports are now aligned with wall-clock time
  • NEW: Reporting time no longer contains gaps in coverage
  • FIX: Per-account number of sessions only shows largest host

2.2.2 - Release esb3032-1.0.0

First official release

Build date

2023-02-14

Release status

Type: production

Change log

  • NEW: Create user documentation for ACD Aggregator
  • NEW: Simplify configuration . Changed from YAML to TOML format.
  • NEW: Handle account records arriving late
  • FIXED: Aggregator hangs if committing to Kafka delays more than 5 minutes

2.2.3 - Release esb3032-1.2.1

Production release

Build date

2023-04-24

Release status

Type: production

Breaking changes

No breaking changes

Change log

  • NEW: Port Account Monitor functionality for Convoy Request Router
  • NEW: Aggregator Performance Improvements
  • FIXED: Reports lost when restarting acd-aggregator

2.2.4 - Release esb3032-1.4.0

Build date

2023-09-28

Release status

Type: production

Breaking changes

None

Change log

  • NEW: Extend aggregator with additional metrics. Per streamer bandwidth and total bandwidth are now updated in Redis. [ESB3032-98]
  • FIXED: Not all Redis instances are updated after a failure [ESB3032-99]
  • FIXED: Kafka consumer restarts on Partition EOF [ESB3032-100]

3 - ACD Cache

Information about the ACD Cache Orbit version is available in EDGS-103 Orbit TV Server User Guide1 and information about the ACD Cache SW Streamer version is available in EDGS-171 SW Streamer User Guide1.


  1. If you don’t have an Edgeware Support account please contact us here↩︎ ↩︎

4 - ESB3013 BGP Sniffer

Information about the ACD BGP Sniffer is available in EDGS-214 ESB3013 User Guide1.


  1. If you don’t have an Edgeware Support account please contact us here↩︎

5 - Edgeware CDN Management System

Information about the classic Edgeware CDN Management System (aka Convoy) is available in EDGS-069 Convoy Management Software User Guide1.


  1. If you don’t have an Edgeware Support account please contact us here↩︎

6 - ESB3008 Edgeware CDN Request Router

Information about the convoy based Edgeware CDN Request Router is available in EDGS-197 ESB3008 HTTP Request Router - User Guide1.


  1. If you don’t have an Edgeware Support account please contact us here↩︎