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.

• 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 we move one cluster member, all of the other members of the cluster are automatically relocated to the new core group.

We 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 appserver, a deployment manager, or a node agent are slightly different. Depending on whether you are moving an appserver, a dmgr, or a node agent, complete one of the following steps.

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

 

• Move one or more appservers to another core group.

  1. Stop the appservers to move.

  2. In the admin console ...

     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 to move.

  4. On the configuration page 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 appservers, node agents, and dmgrs that are members of this core group.

  5. In the Select column, select the appservers that you want to move to a new core group.

     We can only designate one target core group to which to move the selected appservers. If we need to move some of the appservers on this list to two or more other core groups, we 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 admin console page is displayed. This page lists the appservers that you selected to move and the core group to which they currently belong.

  7. Select the core group to which you want these appservers moved. The pull-down, under To core group, lists the core groups that are available on the system.

  8. Click Apply, and then click Save.

  9. Click System Administration > Node agents, select all running nodes, and then click Synchronize to synchronize the configuration changes to all of the running nodes.

  10. Restart the appservers that you moved.

• Move one or more node agents to another core group.
  1. Stop the node agents to move.

  2. In the admin console ...

     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 to move.

  4. On the configuration page 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 appservers, node agents, and dmgrs that are members of this core group.

  5. In the Select column, select the node agents to move to a new core group.

     We can only designate one target core group to which to move the selected node agents. 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 page displays. This page 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 the 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: This synchronization must be performed before you restart the moved node agent.

  10. Restart the node agent that you moved.

• Move the dmgr to another core group.

  1. Stop the dmgr.

  2. Issue the wsadmin –conntype NONE –lang jython command from the profile_root/deployment_manager_profile/bin directory to start a local mode scripting session under the dmgr profile.

  3. In the local mode scripting session, move the dmgr using the following command.

     AdminTask.moveServerToCoreGroup("-source <source_Core_Group> - target <target_Core_Group> -nodeName <mynode> -serverName <myserver>")

  4. Issue the AdminConfig.save() command to save the configuration changes.

  5. Restart the dmgr.

  6. Click System Administration > Node agents, select all running nodes, and then click Synchronize to synchronize the configuration changes to all of the running nodes.

 

Results

After all of the restarts complete, all moved appservers, node agents, and dmgrs should belong to their new core group.

 

Next steps

• We can verify that the servers are in the correct core groups. For each core group, in the admin console ...

  Servers > Core Groupscore_group_name > Core group servers, and look at the list of core group members that displays.

• We can set up core group bridges if any of the core groups need to communicate with each other. See the topic, Core group communications using the core group bridge service, for more information.

Core group server move options

 

Related concepts

Core groups (high availability domains)
Core group communications using the core group bridge service

 

Related tasks

Set up a high availability environment