High availability configuration

Hello,

I am in the process of replacing two aging web servers. The platform of choice is RHEL. These servers must be in a high availability configuration.  I'm am looking at suggestions on how to do this.  Is clustering the right answer?  A college of mine several months ago started looking into ricci and luci as his answer.  I don't know know if that is the right answer or not. 

This environment will consist of one primary server and a secondary.  When the primary gets updated, the secondary should be automatically updated as well and then the primary should be able to fail over to the secondary automatically.

Anyone have any expereince with this type of configuration?  Any suggestions?

Thank you.

Daryl