Clusters and node groups

Node groups bound clusters. All cluster members of a given cluster must be members of the same node group.

Any application you install to a cluster must be able to execute on any application server that is a member of that cluster. For the application you deploy to run successfully, all the members of the cluster must be located on nodes that meet the requirements for that application.

In a cell that has many different server configurations, it might be difficult to determine which nodes have the capabilities to host your application. A node group can be used to define groups of nodes that have enough in common to host members of a given cluster. All cluster members in a cluster must be in the same node group.

All nodes are members of at least one node group. When you create a cluster, the first application server you add to the cluster defines the node group that bounds the cluster. All other cluster members you add to the cluster can only be on nodes that are members of this same node group. When you create a new cluster member in the administrative console, you are allowed to create the application server on a node that is a member of the node group for that cluster only.

Nodes can be members of multiple node groups. If the first cluster member you add to a cluster has multiple node groups defined, the system automatically chooses the node group that bounds the cluster. We can change the node group by modifying the cluster settings. Use the Server cluster settings page to change the node group.

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See Also

Clusters and workload management
Node group
Node group membership rules

 

Related Tasks

Creating clusters
Manage node groups
Manage node group members

 

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