From HowtoForge here's the documentation About linux cluster. God bless HF:)
This guide shows how you can set up a two node, high-a

Reference:
http://www.howtoforge.com/high_availability_heartbeat_centos
MYSQL:
We’re going to go through the entire process of installing, configuring and testing DRBD, Heartbeat and MySQL running in a 2 node cluster environment. This will be a general configuration for learning.
Best practices and security will take a back seat while we learn how all the different pieces work together.
http://almamunbd.wordpress.com/2009/05/28/how-to-configure-mysql-high-availability-with-drbd-and-heartbeat-on-centos-5-3/