Understanding JBOSS Clustering

Clustering is the act of running the same application on multiple application server
instances simultaneously with each application server being aware of the others in the
cluster. An application server that’s part of a cluster is known as a node. But just having
nodes aware of other nodes in a cluster isn’t interesting. The nodes in the cluster must
be able to communicate with each other to do something useful, such as replicating
state or providing failover capabilities. Before we dive into the specifics of the clustering
features that JBoss offers, let’s examine some of the fundamental concepts behind
clustering. And, because you can’t seem to talk about clustering without talking about
load balancing, let’s start with that.