Rolling Deployments

Sorry if this has been discussed before.

Our setup:

4 Node cluster using production profile sitting behind an apache load balancer.

Here is what we want to do.

On application updates we want to remove one node from the cluster and update and test the software on that isolated node.

This would give us a 3 node cluster, with node 4 not participaiting in the cluster: no jboss cache update, no session replication etc.

Telling apache to not use that node is the easy part.

Does anybody know the best way to do this.  Also we do not have the JBoss Operations Network software.

Thanks.