Tomcat: The Definitive Guide

Chapter 10. Tomcat Clustering

In this chapter, we detail the process of clustering Tomcat, which involves setting up multiple machines to host your web applications. There are several significant problems related to running your web application on a single server. When your web site is successful and begins to get a high volume of requests, eventually a single server computer just won’t be able to keep up with the processing load. Another common problem of using a single server computer for your web site is that it creates a single point of failure. If that server fails, your site is immediately out of commission. Regardless of whether it’s for better scalability or for fault tolerance, you will want your web applications to run on more than one server computer. This chapter shows you how to set up a clustered Tomcat system that does exactly that.

Warning

Clustering is an advanced topic, and it is not useful to everyone. Also, as of this writing, the code that makes clustering possible with Tomcat 4.1 is experimental code. You should perform your own testing to ensure that clustering works in your environment. However, you cannot assume that the clustering code has been comprehensively tested by anyone else, including the original authors!

Giving all of the details of clustering techniques, or even exhaustively covering how a particular clustering product works, is beyond the scope of this book. There are numerous ways to cluster any network service, but we can only show you a couple ...