The first post of this series focused on the basic concepts behind clustering JBoss AS 7 and EAP 6. We explained how to enable cluster capabilities for a simple Java EE application and setup a basic cluster environment in the standalone operation mode. In this post we will now explain the domain mode and how to manage a cluster environment in managed domains.
A managed domain spans over multiple hosts with centralized administration and management policies. Each host that runs in domain mode can contain several server instances that belong to one domain. The domain mode is one of two possible operating modes of the EAP 6 respectively the JBoss AS 7. The other mode is the standalone mode. A JBoss application server, which operates in the standalone mode, is an independent process. This mode is pretty similar to the previous versions of the JBoss application server. The different operating modes have no influence to the capabilities of the application server, but rather how to manage one or multiple servers. So, the domain mode is completely independent from clustering. But it provides many useful features for managing clustered environments such as handling of deployments for multiple instances. For example the JBoss AS 7 running in standalone mode does not support any more the previous farming deployment capabilities. Now, this can be done with the domain mode capabilities and of course there are more features such as starting and stopping servers from one single console that makes it easier to handle clustered environments.