A WebLogic Server cluster consists of multiple WebLogic Server instances running simultaneously and working together to provide increased scalability and reliability. A cluster appears to clients to be a single WebLogic Server instance. The server instances that constitute a cluster can run on the same machine, or be located on different machines. You can increase a cluster's capacity by adding additional server instances to the cluster on an existing machine, or you can add machines to the cluster to host the incremental server instances.
The following describes the steps you can take to manage WebLogic Server clusters:
Understand WebLogic Server clusters and cluster configuration. More
Monitor WebLogic Server clusters. How?
Control server instances in a cluster. How?
Configure WebLogic Server clusters. How?
For more information, see these topics in Administering Clusters for Oracle WebLogic Server: