In an article at Java World, Graham King outlines the use of Tomcat clustering and load balancing to keep web applications running happily.

In this article, author Graham King presents simple steps for connecting a pair (or more) of Tomcats to Apache using the JK2/AJP (Apache JServ Protocol) connector and to each other using Tomcat 5’s clustering capabilities. Any of the Tomcat servers can be stopped or started without affecting users. With an Apache/Tomcat cluster in place, you can easily adjust your configuration for a range of load-balancing and failover scenarios.