For a cluster with multiple server instances, using a load balancer in front of the server instances not only simplifies the client's view of the system through a single address, but also improves the overall system's reliability. If one server fails, the load balancer can detect the failure and distribute the load to other live server instances. In this section, we will discuss the load balancer support in GlassFish, and how to configure it.
GlassFish can work with a variety of load balancers, both hardware and software based. For example, the GlassFish project maintains and releases a load balancer plug-in, which works with Apache, Sun Java System Web Server, and Microsoft IIS. The load balancer plug-in is freely downloadable at http://download.java.net/javaee5/external/<os>/aslb/jars, where<os>
indicates the operating system on which the web server is running.
Also, GlassFish can be load balanced by Apache using mod_jk
. However, the mod_jk
based load...