Prefix-list Agent for Arista EOS

Periodically retrieve data from the IRR and build prefix-list objects on EOS.

Overview

The PrefixListAgent is an EOS SDK based agent that runs under ProcMrg on an Arista EOS based device or VM.

The agent maintains up-to-date prefix-list policy objects for use in EOS routing policy configurations, based on data in the IRR.

The agent will periodically check the running configuration of the device to gather a list of prefix-lists that it is responsible for maintaining. It will then retrieve the required data from the IRR via an RPTK web service, and update the prefix-lists without calling the EOS config parser.

Installation

From RPM (recommended)

Install the agent as an EOS extension:

ar#copy https://github.com/wolcomm/eos-prefix-list-agent/releases/download/0.1.0a8/prefix_list_agent-0.1.0a8-1.noarch.rpm extension:
ar#extension prefix_list_agent-0.1.0a8-1.noarch.rpm
ar#sh extensions
Name                                      Version/Release    Status    Extension
----------------------------------------- ------------------ --------- ---------
prefix_list_agent-0.1.0a8-1.noarch.rpm    0.1.0a8/1          A, I      1


A: available | NA: not available | I: installed | NI: not installed | F: forced

Persist the extension to be installed on boot:

ar#copy installed-extensions boot-extensions
Copy completed successfully.
ar#sh boot-extensions
prefix_list_agent-0.1.0a8-1.noarch.rpm

Using pip

This method is not recommended unless you know what you are doing. Without additional configuration, the installation will not persist across reloads.

Drop to the shell:

ar#bash

Install from PyPI:

$ sudo pip install prefix-list-agent

Agent Configuration

Daemon

Configure the agent as an EOS "daemon":

ar#conf t
ar(config)#daemon PrefixListAgent
ar(config-daemon-PrefixListAgent)#exec /usr/bin/PrefixListAgent

Tracing

Enable tracing using the EOS agent tracing infrastructure, e.g.:

ar(config)#trace PrefixListAgent-PrefixListAgent setting PrefixList*/0-6

Set Configuration Options

Set configuration options using the command:

ar(config-daemon-PrefixListAgent)#option <option-name> value <option-value>

Available configuration options are:

• rptk_endpoint (default: None, required):

  The RPTK web service endpoint to connect to when retrieving prefix-list data.

• source_dir (default: /tmp/prefix-lists):

  The local directory to write prefix-list files to.

• refresh_interval (default: 3600):

  The interval between prefix-list updates.

Start the Agent

ar(config-daemon-PrefixListAgent)#no shutdown

Prefix-List Configuration

The PrefixListAgent will check the running configuration for source-based prefix-lists matching the form:

ip[v6] prefix-list ${irr_object} source file:${source_dir}/${policy}/${file_name}

Where:

• ${irr_object}: The IRR object (aut-num or as-set) to build the prefix-list from.
• ${source_dir}: The configured source_dir, as above.
• ${policy}: The resolution policy to use when resolving the IRR object to a prefix-list. Must be a valid policy available on the RPTK web service. You can check the available policies with:

$ curl -q ${rptk_endpoint}/policies | jq

• ${file_name}: The file to write the resulting prefix-list data to. This name should be unique per resolution policy.

After the next update, you should be able to see the entries with:

ar#show ip[v6] prefix-list ${irr_object} detail