Defining zones for container servers

Zones are collections of container servers. A container server can belong only one zone. A container server is assigned to a zone when it starts.

About this task

You must plan your zones before you start your container servers because container servers define their zone membership at startup. If you want to change the zone membership of a container server, you must restart the server with the new zone information.

Procedure

How you define zones depends on if you are using stand-alone container servers or container servers that are running within WebSphere® Application Server:

  • Define zones for stand-alone container servers.
    1. Use the -zone parameter of the startOgServer [Version 8.6 and later]or startXsServer script to specify the zone for all the containers in the started server. For more information about starting servers, see Starting and stopping stand-alone servers.
    2. You can also zone names when you are starting container servers programmatically with the embedded server API. For more information, see Using the embedded server API to start and stop servers.
  • Define zones for container servers that are running within WebSphere Application Server.

    You can use node groups to place container servers in specific zones. Use the following syntax to name your node group to assign it a zone: ReplicationZone<identifier>. When you define zones in the deployment policy, you must name the zones exactly as you named the node groups. The node group name and the zone name in the deployment policy descriptor XML file must be identical

    Important: WebSphere Application Server does not prohibit nodes from being in multiple node groups. Because container servers can be only one zone, ensure that your nodes are in exactly one ReplicationZone node group.

    For example, divide four nodes into two zones, A and B.

    1. Configure four nodes: node1, node2, node3, and node4, each node having two servers.
    2. Create a node group named ReplicationZoneA and a node group named ReplicationZoneB.
    3. Add node1 and node2 to ReplicationZoneA and add node3 and node4 to ReplicationZoneB.
    4. Define ReplicationZoneA and ReplicationZoneB in your deployment policy descriptor XML file. See Example: Zones in a WebSphere Application Server environment for an example.
    5. When the servers on node1 and node2 are started, they join ReplicationZoneA, or zone A in the WebSphere eXtreme Scale configuration. The servers on node3 and node4 join ReplicationZoneB, as zone B in the WebSphere eXtreme Scale configuration.