HOWTO set up a MySQL Cluster for two servers (three servers required for true redundancy)

Introduction of setting up a MySQL Cluster

This HOWTO was designed for a classic setup of two servers behind a loadbalancer. The aim is to have true redundancy - either server can be unplugged and yet the site will remain up.

Notes:

You MUST have a third server as a managment node but this can be shut down after the cluster starts. Also note that I do not recommend shutting down the managment server (see the extra notes at the bottom of this document for more information). You can not run a MySQL Cluster with just two servers And have true redundancy.

Although it is possible to set the cluster up on two physical servers you WILL NOT GET the ability to "kill" one server and for the cluster to continue as normal. For this you need a third server running the managment node.

I am going to talk about three servers:

mysql1.domain.com   192.168.0.1
mysql2.domain.com   192.168.0.2
mysql3.domain.com   192.168.0.3

Servers 1 and 2 will be the two that end up "clustered". This would be perfect for two servers behind a loadbalancer or using round robin DNS and is a good replacement for replication. Server 3 needs to have only minor changes made to it and does NOT require a MySQL install. It can be a low-end machine and can be carrying out other tasks.

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