Creating a server cluster

Use this task to create a server cluster, which is a set of servers that are managed together and participate in workload management.

Before you begin

Before you can create a server cluster, you must have created a managed node in a deployment manager cell. You can do this by federating either a stand-alone server (as the first managed node) or a custom node to the deployment manager..

Why and when to perform this task

If you want to balance workload, such as service requests, over a set of servers, you can create a server cluster, then add servers as members of that cluster. You can also create a backup cluster, to provide failover support for the server cluster that it is assigned to.

To create a server cluster, use the administrative console to complete the following steps:

Steps for this task

  1. In the navigation pane, click Servers > Clusters.
  2. Click New.
  3. On the Enter basic cluster information. page, specify the following details:
    1. For Cluster name, type a name for the cluster.
    2. Optional: To disable node-scoped routing optimization, clear Prefer local.

      By default, the Prefer local option is selected. This indicates that, if possible, Enterprise JavaBean (EJB) requests are routed to the client node. If you enable this feature, performance is improved because client requests are sent to local enterprise beans.

    3. Optional: To create a replication domain for this cluster, select Create a replication domain for this cluster.

      Use replication domains to transfer data, objects, or events for session manager, dynamic cache, or stateful session beans among the application servers in a cluster. Create a separate replication domain to use with each component that acts as a consumer of the replication. For example, you can configure one replication domain to use with a session manager and another domain to use with dynamic cache. The replication domain name that is created is identical to the cluster name.

      For more information about using replication domains, see Replicating data across application servers in a cluster.

    4. Click Next.
  4. On the Create cluster members page, specify details of any cluster members that you want to create with the cluster. You can create cluster members (servers in the cluster) at this time, or add new members to the cluster after creating the cluster.

    For each new cluster member, perform the following actions:

    1. For Member name, type the name of a new server to add as a member of the cluster.
    2. For Select node, select the node on which the server runs.
    3. For Weight, specify the server weight.

      The weight value controls the amount of work directed to the server. If the weight value for the server is greater than the weight values assigned to other servers in the cluster, then the server receives a larger share of the workload. The value can range from 0 to 20.

    4. Make sure that Generate Unique Http Ports is selected. By generating unique HTTP ports for the server, you avoid potential port collisions and configurations that are not valid.
    5. Under Select template:, select the template that you want to use to create all members of the cluster. The template can either be a default server template or an existing server that was created from the required template. If you want the cluster to support service applications for mediation modules on an enterprise service bus, select one of the following from the drop down lists provided:
      • The server template defaultESBServer (distributed platforms) or defaultESBServerZOS (z/OS platform)
      • An existing application server that you know was created from the server template defaultESBServer (distributed platforms) or defaultESBServerZOS (z/OS platform).

      For more information about the templates, see Server templates.

    6. Click Apply to finish the cluster member. You can add more cluster members now or later. All cluster members you add are based on the same server template, so there are less steps to complete.
    Each cluster member that you specify now is added to the list displayed. You can use the Edit function to edit the properties of a cluster member in the list. You can use the Delete function to remove a cluster member from the list.
  5. Click Next.
  6. Check the details on the View the summary page. To create the cluster click Finish.
    • Check that the server template indicated is correct; for example: Clone Template = defaultESBServer
    • If more than one node group bounds the selected node, the node group DefaultNodeGroup is chosen by the system. After creating the cluster, you can change the bounding node group in the Server cluster configuration view.

    If any of the details that you selected are incorrect, you can click Previous, to return to earlier pages and change the details.

  7. Save your changes to the master configuration. As part of saving the change to the configuration, you can select Synchronize changes with Nodes before clicking Save on the Save page.
  8. Before you can start the cluster, the configuration needs to be synchronized to the nodes. If you selected Synchronize changes with Nodes when saving your configuration in the previous step, you can ignore this step.
    Otherwise, take one of the following actions:
    • If you are using automatic synchronization, wait until synchronization runs.
    • Run manual synchronization to get the configuration files moved to the nodes.
      1. Click System administration > Nodes
      2. On the Nodes page, select the node name.
      3. Click Synchronize or Full resynchronize.
      The Nodes page displays status indicating whether the node is synchronized.

What to do next

If the cluster is to support mediation modules, use the Configure your Network Deployment Environment guided activity to configure the cluster for the SCA runtime, as described in Configuring servers or clusters for the SCA runtime.

You can display the properties and local topology of the cluster. Click Servers > Clusters > [Content pane] cluster_name.

You can change the configuration of the cluster. Note that if you have not clicked Save and saved your administrative configuration, you only see the Configuration and Local Topology tabs. To see the Runtime tab, you must save your administrative configuration. Also, ensure that changes are synchronized to the nodes as described above.

You can create more cluster members or Starting clustersstart a server group. For more information about cluster configuration options, see Balancing workloads with clusters.

You can use scripting to automate the task of creating clusters. For information about using scripting for clusters, see Creating clusters using scripting.

To manage a server cluster, you can use the Server cluster collection. You can use this page to display the properties and topology of a cluster, and to make changes as needed.


Last updated: Wed 06 Dec 2006 07:08:08

(c) Copyright IBM Corporation 2005, 2006.
This information center is powered by Eclipse technology (http://www.eclipse.org)