Apache HTTP Server ("Apache") is a well-known web server which can be extended using plug-ins. The Apache Tomcat Connector mod_jk is a plug-in designed to allow request forwarding from Apache HTTP Server to a servlet container. The module also supports load-balancing HTTP calls to a set of servlet containers while maintaining sticky sessions.
HTTP session replication is used to replicate the state associated with web client sessions to other nodes in a cluster. If one node becomes unavailable, another node in the cluster continues to service the failed node's requests. This involves two distinct operations:
Load balancing must be handled externally to JBoss, via either hardware or software. A cost-effective way of enabling load balancing is to set up a software load balancer using Apache HTTP Server and the Apache Tomcat Connector (mod_jk).