jjn1056/postgres-replication-lab

A Vagrant setup that creates a three-node PostgreSQL replication-friendly environment

PostgreSQL Replication Lab

What's Here

This Vagrantfile and related Puppet manifests sets up a three-node lab environment for experimenting with PostgreSQL replication. Each node is initially configured identically:

• Ubuntu 12.04 LTS (from Ubuntu's cloud images)
• PostgreSQL 9.2 (from apt.postgresql.org)
  • Network access from the 192.168.50.0/24 network (including the host system).
• SSH keys configured to allow SSH between the nodes
• Extremely simple scripts for wiring up replication

Getting Started

1. Run ./mk-keys to create host keys and the postgres user's SSH key.
2. Add the IP addresses of the VMs to your host system's /etc/hosts (see below).
3. Run vagrant up to create and configure the VMs.
4. Enjoy!

The Included Scripts

There are two included scripts that can be used to initialize the replicas. For example, to configure both beta and delta as streaming replicas of alpha:

root@beta# sudo -u postgres /vagrant/scripts/reset-replica alpha
root@delta# sudo -u postgres /vagrant/scripts/reset-replica alpha

Or, to set up a replication chain from alpha through beta to delta:

root@beta# sudo -u postgres /vagrant/scripts/reset-replica alpha
root@delta# sudo -u postgres /vagrant/scripts/reset-replica beta alpha

The included seed-replica script can be used to prepare a replica prior to running reset-replica. Read the scripts for details; they're short.

/etc/hosts

Adding the following entries to /etc/hosts on your host system will make it easier to use these VMs:

192.168.50.20    alpha
192.168.50.21    beta
192.168.50.22    delta

The Vagrantfile includes instructions to Virtualbox to use the host resolver, so these hosts entries will also provide name resolution for inter-VM communication.