Load-balanced, fault-tolerant MDBs in HAJMS

NOTE: This example is a contribution from a user.

You should use hajndi-jms-ds.xml not the jms provider in this example. TODO: update this example

Load-balancing message processing with MDBs is one of the best ways

to distribute load across a cluster because the node with the least

activity will process the message (as opposed to a round-robin

load-balancing algorithm which could continue to place load on an

already overloaded node).  The 3.2.4RC2 (April 13, 2004 drop) does

not have load-balancing capabilities for MDBs across a cluster.

Meaning, you cannot distribute the processing load across MDBs

that are deployed on nodes other than the HASingleton node.  For

instance, if you deploy an MDB on a non-master node in HAJMS, it will

fail because the proper JMS services are not configured locally (they

only exist on the master node!).

The attached example, load-balanced-mdbs-example.zip, describes

how to setup JBoss HAJMS for load-balancing your message

processing across a cluster using MDBs.     It uses a custom JMS

Provider that allows MDBs to connect to the JMS HASingleton node and

process messages from it whether they are deployed on the master node

or not.  When the singleton HAJMS server fails and another is

selected, the custom JMS Provider re-connects (DLQHandlers,

JMSContainerInvoker, etc.) to the new master node's resources whether

the new master node is the local server or another remote server.

The MDBs on live nodes keep on processing messages!