Clustering

A cluster is a group of GlassFish server instances, working in coordination.

Clustering provides:
       
         High Availability
         Load Balancing
         Scalability.

There are two types of clustering

Horizontal Clustering:

 A horizontally clustered environment contains multiple physical machines.

Vertical Clustering:

A vertically clustered environment contains multiple application server instances hosted on the same physical machine .

Creating a Cluster:

** You cannot add an existing instance to a cluster.

Through asadmin:

asadmin>create-cluster  ClusterName  --port  4848

Through Admin Console:

Click on Clusters and click new.

Creating an Instance and adding it to a cluster:

Through asadmin:
asadmin>create-instance  --node  NodeName  --cluster  ClusterName  --port  4848  InstanceName

Through Admin Console:

Click on Cluster you have created. Click on Instances and click new.