Same MDB Subscriber Deployed On Multiple Server Question

[joshlam]

We have a situation in which we have to deploy the same MDB on multiple machines for fail over/load balancing purposes. One of the MDB is a subscriber to a certain topic, however, this MDB will be deployed on at least two separate machines running jBoss 3.2.2.

Is there a way to prevent an MDB subscriber to receive and process a topic if the other one got it first? We just don't want to process a topic twice.

Thanks,

[adrian.brock]

You might be able to use two new features available in 3.2
to do this.

1) You can deploy the mdbs in an inactive state.
Using the following invoker-proxy-binding config:

<invoker-proxy-binding>
inactive-message-driven-bean
<invoker-mbean>default</invoker-mbean>
<proxy-factory>org.jboss.ejb.plugins.jms.JMSContainerInvoker</proxy-factory>
<proxy-factory-config>
DefaultJMSProvider
StdJMSPool
15
1

10
false <!-- !! HERE !! -->

queue/DLQ
10
0


</proxy-factory-config>
</invoker-proxy-binding>

2) Write a HASingleton to enable delivery on one node,
this is a JMX invocation on the MDB invoker
http://www.onjava.com/pub/a/onjava/2003/08/20/jboss_clustering.html?page=1

You will find the MDB invoker in the jboss.j2ee domain
on http://localhost:8080/jmx-console
It will have binding=inactive-message-driven-bean
if you used the above config.
You will notice the start/stopDelivery operations.

One question, are these durable subscriptions?
You should not be able to connect to the same durable
subscription twice, since that would require you to use
the same ClientID on two different connections.
You should receive an error message when the
second connection tries to connect.

Regards,
Adrian