#postgres-xc

####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 postgres_xc
   • What postgres_xc affects
   • Setup requirements
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 - How to contribute to the module

##Overview

Postgres-XC (PG-XC) module. Configures a basic cluster and manages PG-XC service.

##Module Description

This module does not install PG-XC. It configures a Postgres-XC cluster on Debian system. It adds service script.
It adds bash scripts enabling high availability.

##Setup

###What postgres_xc affects

• PG-XC configuration file
• PG-XC service

###Setup Requirements

PG-XC should be downloaded and compiled from source.

PG-XC configures a cluster so it needs to be declared on many nodes.

This tutorial/module is designed for a 4 machines environment. The 4 hostnames are database1, database2, gtm and gtm2. GTM standby is installed on gtm2

Datanode_slave needs a ssh free password authentification between the two datanodes for data replication (by rsync)

To get High Availability the Postgres-xc documentation advises to install datanode, coordinator and gtm proxy process on the same server. GTM and GTM standby have to be installed on two other machines.

I use "database" to indicate the node with coordinator, datanode and GTM proxy.

For more information, you should read official PG-XC tutorial. This module configures the same cluster with a GTM standby. (GTM standby doc). It also installs datanode slave for datanode high availability : datanode HA configuration.

##Usage

Configuring database node

On database1 :

    class { 'postgres_xc': 
      database                  => true,
      other_database_hostname   => 'database2',
      other_database_ip         => '192.168.0.2/24',
      gtm_standby_hostname      => 'gtm2',
      gtm_hostname              => 'gtm',
    }

On database2 :

    class { 'postgres_xc':
      database                => true,
      other_database_hostname => 'database1',
      other_database_ip       => '192.168.0.1/24',
      gtm_standby_hostname    => 'gtm2',
      gtm_hostname            => 'gtm',
    }

Configuring GTM node

On gtm :

    class { 'postgres_xc': 
      gtm     => true,
    }

Configuring GTM standby node

On gtm2 :

    class { 'postgres_xc':
      gtm_standby     => true,
      gtm_hostname    => 'gtm',    
    }

##Reference

###Classes

• postgres_xc: Handles all nodes.
• postgres_xc::database: Handles database node.
• postgres_xc::gtm: Handles GTM node.
• postgres_xc::gtm_standby: Handles GTM standby node.
• postgres_xc::coordinator: Handles coordinator process.
• postgres_xc::datanode: Handles datanode process.
• postgres_xc::datanode_slave: Handles datanode_slave process.
• postgres_xc::gtm_proxy: Handles GTM proxy process.

###Parameters

####super_user PG-XC processes will be launched under this user. If $super_user doesn't exist, it will creates it. default : postgres

####user Create a user named with this parameter. default : echoes

####password Password for the user. default : echoes

####group super_user's group. default : postgres

####home super_user's home directory. default : /var/lib/postgresql

####gtm_port Listening port for gtm process. default : 7777

####gtm_proxy_port Listening port for gtm_proxy process. default : 7777

####datanode_port Listening port of datanode process. default : 5555

####datanode_slave_port Listening port of datanode_slave process. default : 20010

####coordinator_port Listening port for coordinator process. default : 5432 (default postgreSQL port)

####gtm_directory Directory where gtm will be initialise. default : "$home/gtm"

####datanode_directory Directory where datanode will be initialised. default : "$home/datanode"

####coordinator_directory Directory where coordinator will be initialised. default : "$home/coord"

####gtm_proxy_directory Directory where gtm proxy will be initialised. default : "$home/gtm_proxy"

####gtm_standby_directory Directory where gtm standby will be initialised. default : "$home/gtm_standby"

####gtm_name Name of GTM node in configuration file. default : gtm

####gtm_standby_name Name of GTM standby node in configuration file.

####datanode_slave Boolean to install datanode_slave or not default : true

##Limitations

This module has been tested only on Debian sytems.

##Development

Bug can be reported on Github issues tracker

###Changelog

v0.2.0 Support datanode slave