Not sure if this is the right forum, but....

I am designing an enterprise app which, at the moment, is simply an EAR containing an EJB and a Web module. The EJB jar contains JPA entities and a persistence.xml file pointing to a JNDI datasource. That datasource is defined under server/default/deploy/ right now. This is all good, but I have a requirement to be able to deploy multiple instances of this application on the same server (under different URLs). Each instance needs to be able to connect to a different datasource. At the moment, this is the only difference although there could be other differences in the future (like instance specific message queues for example).

Is it possible to deploy the full EAR just once and then, for other instances, just deploy a "configuration" which would include different datasource details?

When this app goes into production there's going to be at least 30 instances to start with, so I really don't want to have to do that many full deployments.

Any suggestions warmly appreciated!