Network Deployment (Distributed operating systems), v8.0 > Establishing high availability

Move 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 to move, and to which core group 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.

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 dmgr, or a node agent are slightly different. Depending on whether you are moving an application server, a dmgr, or a node agent, complete one of the following steps. In general, you should not move a dmgr.

Procedure

• Move one or more application servers to another core group.
  1. Stop the application servers 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 containing the application servers 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 dmgrs that are members of this core group.

  5. In the Select column, select the application servers to move to a new core group.

     We can only designate one target core group to which to move the selected application servers. If move some of the application servers 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 administrative console panel is displayed. This panel lists the application servers 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 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 application servers 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 containing the node agents 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 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. If you need to move some of the node agents 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_name > Core group servers > Move panel displays. This panel lists the node agents 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. You must perform this synchronization 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. Start a local mode scripting session under the dmgr 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 dmgr. Use the following command:

     AdminTask.moveServerToCoreGroup("-source
     <source_Core_Group>
        -target
     <target_Core_Group>    -nodeName
     <node_name> -serverName
     <server_name 
      gt;")
     

  4. Save the configuration changes. Use the following command:

     AdminConfig.save()
     

  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 application servers, node agents, and dmgrs should belong to their new core group.

What to do next

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

  Servers > Core Groups > core_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 Core group communications using the core group bridge service topic for more information.

Related

Core group server move options
Core groups (high availability domains)
Core group communications using the core group bridge service
Set up a high availability environment

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