### To Configure a Cluster

1. In the tree component, expand the Clusters node.

2. Select the node for the cluster.

   On the General Information page, you can perform several optional tasks, detailed in the following steps.

3. (Optional) Click Start Instances to start the clustered server instances.

   The number of instances stopped and started is listed farther down the page.

4. (Optional) Click Stop Instances to stop the clustered server instances.

   The number of instances stopped and started is listed farther down the page.

5. (Optional) Click Migrate EJB Timers to migrate the EJB timers from a stopped server instance to another server instance in the cluster.

6. (Optional) Enable and configure the Group Management Service (GMS) for the instance.

   GMS is a module that provides failure notification for instances in a cluster, and for components such as the transaction service, timer service, ORB and EJB. It also protects computing resources for components that re recovering, allowing for quicker failure recovery.

   1. Click the Enabled checkbox to enable GMS for each instance in the cluster.

   2. Choose a Heartbeat Port for GMS communication for group members.

   3. Chose a Heartbeat Address as the IP address for GMS communication for group members.

7. (Optional) Select the load balancer algorithm for the cluster.

   - Round robin: The load balancer assigns requests to server instances in the cluster equally. For example, if you have two instances in the cluster, the requests are assigned to each instance in turn.

   - Weighted round robin: The load balancer assigns requests based on the weights you specify for the instances on the cluster's Instances tab. For example, if you have two instances in a cluster and assign a weight of 1 to the first instance and three to the second instance, for every four requests one request goes to the first instance and three go to the second instance.

   - User-defined: The load balancer assigns requests based on the load balancer policy you created. Specify the path and the module name in the Module field. If you don't specify a path, the default is the Web Server's `/plugins/lbplugin/include/loadbalancer`

##### More Information
Equivalent asadmin command

`start-cluster`, `stop-cluster`, `migrate-timers`, `set` (for GMS properties), `create-http-lb-ref`

##### See Also

- Broken Link (Target ID: ABDJB)

- To Create Server Instances for a Cluster

- To Configure Applications for a Cluster

- To Configure Resources for a Cluster

- To Delete a Cluster

- To Upgrade Components Without Loss of Service

- To Migrate EJB Timers