galera_arbitrator

Table of Contents

1. Overview
2. Module Description - What the module does and why it is useful
3. Setup - The basics of getting started with galera_arbitrator
   • What galera_arbitrator affects
   • Setup requirements
   • Beginning with galera_arbitrator
4. Usage - Configuration options and additional functionality
5. Reference - An under-the-hood peek at what the module is doing and how
6. Limitations - OS compatibility, etc.
7. Development - Guide for contributing to the module

Overview

This module configures a standalone Galera Arbitrator without touching any other components of the system. It is developed for the RedHat family but should be fairly easy to configure for other distributions.

Module Description

A Galera Arbitrator acts as a lightweight member of a Galera cluster, primarily useful when you need another node in the cluster for quorum. It participates in voting without handling the actual functionality the cluster provides. For example if it is part of a MySQL cluster, it would not serve MySQL at all.

I built this module to be incredibly focused on garbd and not effect anything else on the system.

Setup

What galera_arbitrator affects

• Installs garbd package
• Sets up garbd sysconfig config file

Setup Requirements

• You must have Percona's package repository (or whatever repo contains the packagename specified) configured for this to work, this module does not take care of it for you. There are multiple Puppet modules available that can assist with that. I did not want to force a particular implementation.

Usage

Beginning with galera_arbitrator

If you are running a RedHat based system, all you should have to do is call the module with the list of nodes and cluster name (referred to as cluster group by garbd). Ex:

class { 'galera_arbitrator':
  galera_nodes => '1.1.1.1:4567,2.2.2.2:4567,3.3.3.3:4567',
  galera_group => 'my_galera_cluster',
}

You can also configure it via hiera and simply include galera_arbitrator:

---
galera_arbitrator::galera_nodes: '1.1.1.1:4567,2.2.2.2:4567,3.3.3.3:4567'
galera_arbitrator::galera_group: 'my_galera_cluster'

Parameters for the galera_arbitrator class

• servicename: The service name used with init.d, systemctl, etc. Default: system dependent, see data directory
• packagename: The full package name used with your package manager. Default: system dependent, see data directory
• sysconfig: Full path to the sysconfig file used by garbd. Default: system dependent, see data directory
• ensure_package: Sets the ensure value of the package resource. Default: present
• ensure_service: Sets the ensure value of the service resource. Default: running
• enable_service: Sets the enable value of the service resource. Default: true
• galera_nodes: Comma separated list, or array, of node IP addresses and optional ports using ipaddr:port. required
• galera_group: Galera cluster name required
• galera_options: Optional parameters to pass to garbd
• galera_logfile: Optional log file path (defaults to syslog)

Reference

For more information on how to use the Galera Arbitrator, see: Percona's Latest Garbd Howto

Limitations

Out of the box, this only supports RedHat and Debian style Linux distributions, and only those that are supported by Percona. Most Percona supported Linux distributions should be fairly easy to support by setting servicename, packagename, and sysconfig.

Development

I don't have anything specific to say here aside from, fork it in github.com and submit a pull request! Thank you for your help!

Contributors

• Daniel Henninger, github.com/jadestorm