How to Create Cluster in IBM WebSphere ND?

Step-by-Step cluster creation procedure in IBM WebSphere Application Server (WAS) Network Deployment (ND).

Creating a cluster in IBM WAS ND is one of the essential tasks for WebSphere administrator and necessary to provide application high-availability & workload balancing.

There are a lot of benefits in having an application deployed in cluster mode, like:

• Ensure application is always available from one of the cluster members
• High-availability if one or more JVM is down
• No issue if one of the cluster JVM’s physical server is down
• No or minimum downtime during restart
• Easy maintenance
• No need to deploy on multiple JVM instead just select the cluster as target

There are two types of clustering available to scale your WebSphere applications.

Horizontal Cluster – One of the widely used clustering type where you host your applications on multiple JVM servers (physical or VM) using a single cluster.

Vertical Cluster – having all JVM servers under cluster on single physical or VM server. A vertical cluster can be SPOF (Single point of failure) when a server goes down.

Note: With WebSphere 8.5 or higher you can also create a dynamic cluster which is different from a traditional cluster.

So based on the requirement you got to decide which clustering type to use.

WebSphere cluster creation is possible either through GUI (WAS Administrative Console) or command line (wsadmin/script). The following is through the admin console.

Creating WebSphere Cluster using GUI

• Login to WAD DMGR Admin Console
• Navigate Servers >> Clusters >> WebSphere application server clusters

• Click New >> Enter the “Cluster name” and click Next

• Enter the Cluster member name and select the node where you want to create

You have the option to create the member using an application server template, using an existing JVM as a template, convert existing JVM as a cluster member or create an empty cluster.

• I’ve chosen to create using a default template, click Next
• You can create additional cluster member on next screen if you need, click Next

• Review the summary and click Finish

• Review and synchronize the configuration changes

This concludes cluster is created and ready to be used. Let’s verify.

• Go to WebSphere application servers under “Server Types.”

• As you can see, I’ve created tow JVM under “Cluster-1”. By default, they will be stopped state.

To start, you can either start the JVM or whole cluster

If you have multiple JVM’s in a cluster and need to restart all, then you can restart the whole cluster.

Tip: if you need to create JVM in existing cluster then you can do as following.

• Go to Servers >> Clusters >> WebSphere application server clusters
• Click the Cluster from the list where you want to create a JVM
• Click “Cluster members” under Additional Properties

• Click New
• Enter the JVM name >> select the node where you want to get it created and click “Add Member.”

• Once added, click Next and then Finish

Don’t forget to review and synchronize the changes.

I hope this quick guide helps you understand how to create a cluster in IBM WebSphere Application Server.