How to achieve clustering, load balancing and fail-over for Session Beans in OGS

Question

JBoss seems to have a pretty easy set of annotations/configurations for clustering and load balancing session beans, but I'm not seeing the same features in the GlassFish 3.x docs.

Let's say I have both MyStatefulBean and MyStatelessBean beans. For both of them, I want the following capabilities:

• I want to be able to create a cluster of the bean (to any number or scale) and put them behind a software load balancer that will round robin the beans; and
• If 1 of the clustered beans fails for any reason I want it taken out of the pool

Does GlassFish free/(community edition) even support this or would I have to implement this myself?

Tangential to the first question: does clustering/load-balancing even make sense form stateful beans? I don't think it does now that I think of it...but still the question applies to both types of beans until proven otherwise!

Answer 1

First, you need to enable high availability for the application if you want to preserve the session state on failure. If using the admin console, there is a checkbox for this on the deploy app screen. If you are deploying from the command line, then use "asadmin deploy --availabilityenabled=true --target mycluster myapp.ear".

When the bean is looked up, the bean RMI proxy/stub that is generated has a list of all the clustered GlassFish instances that are available. The order of the servers is randomly generated, and the RMI stub will select the server at the top of the list. This is how the load is spread across the cluster. If the remote server fails, the next server in the list is selected. If the remote bean is a stateful session bean, then the session is preserved on failover.

As @pdudits mentions, please read the documentation on the subject for more in-depth coverage.

Hope this helps!