Moving core group members

When moving members to a different core group, remember that: each process can only be a member of one core group, and that all members of a given cluster must belong to the same core group.

Before you begin

Review the topic, Core groups (high availability domains).
Determine which core group members you want to move, and to which core group you want to move them
If you move one cluster member, all of the other members of the cluster are automatically relocated to the new core group.

About this task

You might need to move one or more core group members:

To populate a newly created core group.
To rebalance existing core groups.

The steps you perform to move either an application server, a deployment manager, or a node agent are slightly different. Depending on whether you are moving an application server, a deployment manager, or a node agent, complete one of the following steps.

Avoid trouble: In general, you should not move a deployment manager.

Procedure

Move one or more application servers to another core group.
1. Stop the application servers that you want to move.
2. In the administrative console, click Servers > Core Groups > Core group settings to display a list of the core groups in the topology.
3. Click the name of the core group that contains the application servers that you want to move.
4. On the configuration panel for this core group, under Additional Properties, click Core group servers to display the list of members of this core group.
  This list includes all of the application servers, node agents, and deployment managers that are members of this core group.
5. In the Select column, select the application servers that you want to move to a new core group.
  
  You can only designate one target core group to which to move the selected application servers. If you need to move some of the application servers on this list to two or more other core groups, you have to repeat this step and the following step for each core group.
6. Click Move.
  The Core Groups > Core group settings > core_group_name > Core group servers > Move administrative console panel is displayed. This panel lists the application servers that you selected to move and the core group to which they currently belong.
7. Select the core group to which you want these application servers moved.
  The pull-down, under To core group, lists the core groups that are available on your system.
8. Click Apply, and then click Save.
9. Click System Administration > Node agents, select all running nodes, and then click Synchronize to synchronize your configuration changes to all of the running nodes.
10. Restart the application servers that you moved.
Move one or more node agents to another core group.
1. Stop the node agents that you want to move.
2. In the administrative console, click Servers > Core Groups to display a list of the core groups in the topology.
3. Click the name of the core group that contains the node agents that you want to move.
4. On the configuration panel for this core group, under Additional Properties, click Core group servers to display the list of members of this core group.
  This list includes all of the application servers, node agents, and deployment managers that are members of this core group.
5. In the Select column, select the node agents that you want to move to a new core group.
  
  You can only designate one target core group to which to move the selected node agents. If you need to move some of the node agents on this list to two or more other core groups, you have to repeat this step and the following step for each core group.
6. Click Move.
  The Core Groups > core_group_name > Core group servers > Move panel displays. This panel lists the node agents that you selected to move and the core group to which they currently belong.
7. Select the core group to which you want these node agents moved.
  The pull-down, under To core group, lists the core groups that are available on your system.
8. Click Apply, and then click Save.
9. Issue the syncNode command from the profile_root/node_agent_profile/bin directory to manually synchronize the updated configuration to the node.
  
  Avoid trouble: You must perform this synchronization before you restart the moved node agent.
10. Restart the node agent that you moved.
Move the deployment manager to another core group.
1. Stop the deployment manager.
2. Start a local mode scripting session under the deployment manager profile.
  Use the following command from the profile_root/deployment_manager_profile/bin directory:
```
wsadmin -conntype NONE -lang jython
```
3. In the local mode scripting session, move the deployment manager.
  Use the following command:
```
AdminTask.moveServerToCoreGroup("-source <source_Core_Group> 
   -target <target_Core_Group>
   -nodeName <node_name> -serverName <server_name>")
```
4. Save the configuration changes.
  Use the following command:
```
AdminConfig.save()
```
5. Restart the deployment manager.
6. Click System Administration > Node agents, select all running nodes, and then click Synchronize to synchronize your configuration changes to all of the running nodes.

Results

After all of the restarts complete, all moved application servers, node agents, and deployment managers should belong to their new core group.

What to do next

You can verify that the servers are in the correct core groups. For each core group, in the administrative console, click Servers > Core Groups > core_group_name > Core group servers, and look at the list of core group members that displays.
You can set up core group bridges if any of the core groups need to communicate with each other. See the Core group communications using the core group bridge service topic for more information.