Managing Oracle Application Server Clusters

This section presents functionality for cluster management. A file-based cluster is created by assigning the file based repository of an Oracle App Server instance as the cluster repository. When an Oracle App Server instance joins the cluster, the instance stops using its repository and starts using the cluster repository. As a consequence, the former instance immediately adopts the configuration described in the cluster repository.

A cluster is composed of one or more J2EEInstaller components. In a cluster, one J2EEInstaller component is the cluster master and additional J2EEInstaller components are members of the cluster. The instance that represents the cluster master has a component called ClusterMaster installed in its virtual host. In a similar way, the J2EEInstaller components that are members of the cluster have a ClusterMember component installed in them.

How to Create a Cluster

Upon completion of this task, the following changes will have been made:

• Your target instance is a cluster.

• One ClusterMaster component is installed in the selected virtual host.

Before You Begin

To create a cluster, you must already have a J2EEInstaller component installed. For more information, see How to Deploy the J2EE and Web Cache Topology.

Steps

1. In the Common Tasks section of the N1 Grid SPS browser interface, select Oracle App Server 10g.

2. In the Cluster Management section of the Oracle App Server 10g Common Tasks page, click Create.

3. On the Plans Details page, click Run.

4. Select the virtual host that you want to target.

   The host must be a member of the ClusterHostSet. Also, the host must not contain a ClusterMaster component or a ClusterMember component. You can select more than one virtual host.

5. Verify that the target host set is not selected.

   The checkbox in front of the target host set should be empty. Otherwise, the plan will try to install in the host set plus the hosts that you selected in the previous step

6. Click Run Plan (includes preflight).

How to Add a J2EEInstaller Component to an Existing Cluster

Upon completion of this task, the following changes will have been made:

• Your target instance is a member of the cluster.

• One ClusterMember component is installed in the selected vhost

• The Oc4jHolder component and all its Oc4jInstance components are removed, because the instance now belongs to the cluster.

• The OC4J instances and applications of any member of the cluster are represented by the components installed in the Oc4jHolder component that belongs to the application server instance holding the ClusterMaster component.

Before You Begin

To assign a J2EEInstaller component to a cluster, the cluster must already exist. See How to Create a Cluster.

Steps

1. In the Common Tasks section of the N1 Grid SPS browser interface, select Oracle App Server 10g.

2. In the Cluster Management section of the Oracle App Server 10g Common Tasks page, click Join.

3. On the Plans Details page, click Run.

4. On the Plans Details Run page, select the virtual host that you want to target.

   The host must be a member of the ClusterHostSet. Also, the host must not contain a ClusterMaster component or a ClusterMember component. You can select more than one virtual host.

5. Verify that the target host set is not selected.

   The checkbox in front of the target host set should be empty. Otherwise, the plan will try to install in the host set plus the hosts that you selected in the previous step

6. Type the value for the ORACLE_HOME_NAME of the J2EEInstaller component that contains the ClusterMaster of the cluster you want to join.

7. Type the name of the physical host on which the ClusterMaster component is installed.

8. Click Run Plan (includes preflight).

How to Remove a J2EEInstaller Component from a Cluster

When an Oracle App Server instance leaves the cluster, the cluster repository is copied into the file-based repository of the instance. From this point on, the instance uses its own repository and commands issued to this instance to modify OC4J instances or applications only affect this instance.

Upon completion of this task, these changes will have been made:

• Your target instance is not a member of the cluster.

• One ClusterMember component is uninstalled in the selected vhost.

• One Oc4jHolder instance is installed in the instance that left the cluster.

• One Oc4jHolderHT vhost is created by the Oc4jHolder component.

• One Oc4jInstance (home) is installed in the Oc4jHolderHT vhost.

The application server instance leaving the cluster inherits a copy of all the OC4J instances and applications that were deployed in the cluster. N1 Grid SPS limitations cannot represent this change, therefore, this instance will be out of sync with the Oracle application. The home OC4JInstance will be created, but other OC4J instances in the cluster and the applications that they contain will be missing. To resynchronize this component with Oracle, you must use a markOnly install or set the full Install parameter to false when you run plans.

Before You Begin

To remove a J2EEInstaller component from a cluster, the component must be a member of a cluster. See How to Add a J2EEInstaller Component to an Existing Cluster.

Steps

1. In the Common Tasks section of the N1 Grid SPS browser interface, select Oracle App Server 10g.

2. In the Cluster Management section of the Oracle App Server 10g Common Tasks page, click Leave.

3. On the Plans Details page, click Run.

4. On the Plans Details Run page, select the virtual host that you want to remove from the cluster.

   The host must be a member of the ClusterHostSet. Also, the host must not contain a ClusterMaster component or a ClusterMember component. You can select more than one virtual host.

5. Verify that the target host set is not selected.

   The checkbox in front of the target host set should be empty. Otherwise, the plan will try to remove components in the host set plus the hosts that you selected in the previous step

6. Click Run Plan (includes preflight).

How to View Cluster Masters

Steps

1. In the Common Tasks section of the N1 Grid SPS browser interface, select Oracle App Server 10g.

2. In the Cluster Management section of the Oracle App Server 10g Common Tasks page, click View Masters.

   A list of the installed ClusterMaster components appears. Each component corresponds to a different cluster.

How to View Cluster Members

Steps

1. In the Common Tasks section of the N1 Grid SPS browser interface, select Oracle App Server 10g.

2. In the Cluster Management section of the Oracle App Server 10g Common Tasks page, click View Members.

   A list of the installed ClusterMember components appears. Each component corresponds to a J2EEInstaller component that is a member of a cluster.

How to Remove a Cluster

To remove a cluster you must first remove all the members of the cluster. Follow the procedures explained in previous sections to do so. Once the cluster has no members, follow these steps to remove the cluster.

Steps

1. In the Application Deployment section of the N1 Grid SPS browser interface, click Components.

2. If needed, select Change Folder and go to /com/sun/oracle10g_AS.

3. Click ClusterMaster.

4. Under component procedures run the default uninstall.

5. Select the ClusterMaster component that you want to remove.