Clustering in WebSphere Application Server

Clustering is a very critical aspect of any middleware enterprise application. It provides capabilities of high availability by providing fail over and load balancing mechanism.

This post is a sample demonstration of configuring a cluster in WebSphere Application Server Network Deployment 7.0.

Prerequisites:

Deployment Manager Profile created using profile management tools.

 

Steps:

1. Create Cluster definition.

Log into WAS Admin console — > Servers — > Clusters — > WebSphere application server clusters.

 

2. Create cluster members.

Provide the details about the cluster members.

 

Define the node on which the cluster member would reside.

Also define whether the server would be generated based on a server template.

You can add additional members to the cluster.

Once the cluster is created successfully, it would be in stopped state by default.

3. Make sure the node agent is started.

Go to System administration from left panel — > Node agents — > Check the status.

 

 

If the Node Agent is not  started, you can execute the below script to start the same.

WAS_HOME/profiles/YOUR_PROFILE_NAME/bin/startNode.cmd

4. Start the cluster.

 

 

Further reading:

http://pic.dhe.ibm.com/infocenter/wasinfo/v6r0/index.jsp?topic=%2Fcom.ibm.websphere.nd.doc%2Finfo%2Fae%2Fae%2Ftrun_wlm_cluster.html

 

Some common issues while configuring a cluster in WebSphere Application Server.

Issues:

1.

Cluster member MyServer1 will not be started because the Node Agent on node Node02 is not active. Cluster members can be started individually from the cluster member collection panel.

Remedy:

Make sure you start the Node Agent.

2.

The node agent on node Node02 must be started to perform the restart operation. Node agents in stopped state cannot be started from the console.

Remedy:

You would need to start the node agent from command line as below.

WAS_HOME/profiles/YOUR_PROFILE_NAME/bin/startNode.cmd

 

3.

 

Caused by: com.ibm.websphere.management.exception.AdminException: ADMU7707E: Failed while trying to determine the Windows Service name for server: nodeagent; probable error executing WASService.exe: com.ibm.websphere.management.exception.AdminException: ADMU7709E: Unexpected exception while processing server: nodeagent; exception = java.io.IOException: Cannot run program “D:SoftwaresbinWASService.exe”: CreateProcess error=740, The requested operation requires elevation.

 

Remedy:

Check whether the node agent service is present or not. If not create a node agent service as below.

 

WAS_HOMEbin> wasservice -add Dmgr01_NodeAgent

-servername server1 -profilePath “D:SoftwaresprofilesDmgr01”

-wasHome “D:Softwares” -logFile “D:SoftwaresprofilesDmgr01logsnodeagentstartNode.log”

-logRoot “D:SoftwaresprofilesDmgr01logsnodeagent” -restart true -startType automatic

 

4.

The node LTADKAW7Node01 is not synchronized with the master configuration. This may prevent cluster member MyServer1 from starting correctly.

Remedy: Synchronize the node.

 

Cheers,

Wonders team 🙂