Clusters

A cluster is a deployment in which multiple WebLogic Server instances run simultaneously and work together to provide increased scalability and reliability. A cluster appears to clients to be a single WebLogic Server instance. The server instances that constitute a cluster can run on the same machine, or be located on different machines. You can increase a cluster's capacity by adding additional server instances to the cluster on an existing machine, or you can add machines to the cluster to host the incremental server instances.

The configuration information for a cluster is stored in config.xml for the domain that contains the cluster. This XML document consists of a series of XML elements. The Domain element is the top-level element, and all elements in the Domain descend from the Domain element. The Domain element includes child elements, such as the Server, Cluster, and Application elements. These child elements may have children of their own.

Each element has one or more configurable attributes. The cluster tabs in the Administration Console allow you to set the values of the configurable attributes for a cluster.

The following topics describe the configuration and monitoring tasks you can perform with the Administration Console.

 

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Tasks

Configuring a Cluster

There are multiple techniques and tools you can use to create and maintain a cluster configuration. For a list, see "Methods of Configuring Clusters" in Using WebLogic Server Clusters.

If you are configuring a new cluster in a new domain, BEA recommends that you use the using the Configuration Wizard. For more information, see "Create a Clustered Domain" in Using WebLogic Server Clusters.

Follow these steps to configure a cluster using the Administration Console:

1. In the left pane, click the Clusters node.

2. In the right pane, click Configure a New Cluster.

3. Enter values for:

   • Name—Assign a unique name to the cluster. Each configurable resource in your WebLogic Server environment should have a unique name.

   • Cluster Address—supply a cluster address that identifies the Managed Servers in the cluster. The cluster address is used in entity and stateless beans to construct the host name portion of URLs. If the cluster address is not set, EJB handles may not work properly.

   • Default Load Algorithm

   • Service Age Threshold

   • Client Cert Proxy Enabled

4. Click Create to create the cluster.

5. Click the Multicast tab.

6. If necessary, edit the default values for:

   • Multicast Address (use a value between 224.0.0.1 and 239.255.255.255)

   • Multicast Port number

   • Multicast Send Delay

   • Multicast TTL

   • Multicast Buffer Size

7. Click Apply.

Cloning a Cluster

Clone a cluster to configure a new cluster based on the configuration of an existing cluster. Edit the attributes that must be unique for each cluster in a domain, such as Cluster Name and Cluster Address.

1. In the left pane, click Clusters.

2. Click the Clone icon in the row of the cluster you want to clone.

3. Enter values for:

   • Name

   • Cluster Address

   • Default Load Algorithm

   • Service Age Threshold

   • Client Cert Proxy Enabled

4. Click Clone to create the new cluster.

5. Click the Multicast tab.

6. As appropriate, edit the values for:

   • Multicast Address (use a value between 224.0.0.1 and 239.255.255.255)

   • Multicast Port number

   • Multicast Send Delay

   • Multicast TTL

   • Multicast Buffer Size

7. Click Apply.

Deleting a Cluster

1. In the left pane, click Clusters.

2. Click the Delete icon in the row of the cluster you want to delete.

3. At the confirmation question, click Yes.

4. Click Continue.

Assigning Servers to a Cluster

Follow these steps to assign server instances to a cluster.

1. In the left pane, expand Clusters.

2. Click a cluster name that you want to add servers to.

3. In the right pane, click the Servers tab.

4. In the Available column, select one or more servers to assign to the cluster.

5. Click the right arrow button.

6. Click Apply.

Monitoring a Cluster

Monitoring a cluster gives you statistics on the activity of each server in the cluster.

1. In the left pane, expand Clusters.

2. Click a cluster name that you want to monitor.

3. In the right pane, click the Monitoring tab.

4. Click Monitor Server Participation in This Cluster.

5. Check the table that shows statistics for each server in the cluster.

6. To change the view, click Customize This View.

7. At Sort Rows By, click the right arrow button to move fields to the Chosen column. This defines the order in which the rows appear.

8. Do the same at Columns to Display. This defines the columns in the table.

9. If necessary, click Use These Settings By Default.

10. Click Apply.

Adding a Note to a Cluster Configuration

1. In the left pane, expand Clusters.

2. Click the name of a cluster to which you want to add a note.

3. Click the Notes tab. Type the note in the Notes field.

4. Click Apply to save your changes.

Start a Cluster

1. In the left pane, expand Clusters.

2. Right-click on the name of the cluster that you want to start.

3. Select Start this cluster.

4. Click Yes.

Kill a Cluster

1. In the left pane, expand Clusters.

2. Right-click on the name of the cluster that you want to kill.

3. Select Kill this cluster.

4. Click Yes.