5.3.5. HOWTO Set Up SIMP’s External Node Classifier

An External Node Classifier, ENC, can be used to determine what Puppet environment is used by a node.

SIMP provides a simple, YAML-based ENC, /usr/local/bin/set_environment, available from the simp-utils RPM. That package will already be installed on your system, if you installed the SIMP server from a SIMP ISO or from RPM.

To use this script for your ENC, do the following as root:

  1. Ensure the script can be executed by the puppetserver.

    chmod g+rX /usr/local/bin/set_environment
    chgrp puppet /usr/local/bin/set_environment
  2. Configure Puppet to use this script as an ENC

    Set the following in the [server] section of /etc/puppetlabs/puppet/puppet.conf:

    1. Add or change the line node_terminus to exec.

    2. Set the external_nodes entry to /usr/local/bin/set_environment.

    The resulting lines should look something like this:

    node_terminus = exec
    external_nodes = /usr/local/bin/set_environment
  3. Add a file /etc/puppetlabs/puppet/environments.yaml to your system.

    This file defines the mapping of nodes to environments.

    • Each rule in this file should have the form

      <regular expression or FQDN>: 'environment name'.

    • The rules are processed from top down, and the first match wins.

    For example,

    # The puppet server will use the production environment
    'puppet.my.domain':            'production'
    # Any node in my.domain whose FQDN begins with test will use the test environment
    '/^test([0-9])+\.my\.domain/': 'test'
    # Default to the production environment in all other cases
    '/^.*$/':                      'production'

    To verify the file is properly formatted and yields the classification desired run the script manually with a node’s FQDN. It should return

    environment: <node's Puppet environment name>

    Using the above environments.yaml file, the following command should return

    environment: test

    /usr/local/bin/set_environment test11.my.domain
  4. Ensure the puppetserver can access the ENC’s configuration file

    chmod g+rX /etc/puppetlabs/puppet/environments.yaml
    chgrp puppet /etc/puppetlabs/puppet/environments.yaml
  5. Restart the puppetserver service

    # On EL7
    systemctl restart puppetserver

For more information on ENCs, please see Puppet’s ENC documentation.