WebLogic 12c : Dynamic Clusters

Oracle introduced a new interesting feature in WebLogic release 12.1.2: dynamic clusters.  With this option you can easily roll out new clusters and scale them out.

In this blog post, I will try to describe this new feature.

Starting point:
WebLogic development domain "dynamic_domain" with the admin server running on port 7001.
Domain is located on 1 machine where the NM is running on.

Navigate to the WLS console and go to the clusters section.
Choose for "New - Dynamic Cluster":

Choose an appropriate name for the cluster, e.g. "MyDynamicCluster".

In the next step, you can define a number of dynamic servers and a server name prefix.  I keep the defaults here:

Next, you can choose the machines for the managed servers.  Because I have only one machine, I keep the default here.

Next, you can define the listen ports for the servers; you have the choice between unique and fixed listen ports.  I keep the default unique value.

The last screen shows an overview.

Terminating this wizard results in the following:
(1)
Of course, the cluster itself: "MyDynamicCluster".

(2)
A server template called "MyDynamicCluster-Template".  Afterwards, you can change the settings of it.

(3)
Two automatically created managed servers.

Both servers can be started in the console through the NM.

When you go into the dynamic cluster, and navigate then to the "Configuration - Servers" tab, you can see the 2 created servers.  Also, you have the possibility to change some parameters of the dynamic cluster.

For example, if you modify the "Maximum Number of Servers" from 2 to 3, WLS will automatically create a third server for you.

When all servers of the dynamic cluster are down, you can delete the cluster.  If at least one server is still running, you'll get an error and you are not able to delete the cluster.
After the cluster has been deleted, you'll notify that the managed servers are deleted as well.  The server template still exists, but has of course no more a link with the cluster.