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
   • 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
   • WebLogic Plug-In Enabled
   • 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.
8. In the right pane, click the Servers tab.
9. In the Available column, select one or more servers to assign to the cluster.
10. Click the right arrow button.
11. 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
   • WebLogic Plug-In Enabled
   • 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.
8. In the right pane, click the Servers tab.
9. In the Available column, select one or more servers to assign to the cluster.
10. Click the right arrow button.
11. 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

The Cluster-->Monitor page displays current status of the cluster, and statistics on the activity of each Managed 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. The Monitoring page displays the number of servers configured for the cluster, the number of servers currently participating in the cluster, and in tabular form, key statistics on each Managed Server's recent activity.

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 all Servers in Standby Mode

Use this command to start clustered Managed Servers in standby mode with Node Manager. The following prerequisites apply:

• To start a Managed Server from the Administration Console using Node Manager, a Node Manager process must be running on each machine that hosts Managed Server in the cluster. For more information, refer to "Starting Node Manager."
• Starting server instances in standby mode requires a domain wide Administration Port.
• For information about the capabilities, limitations, and prerequisites for an Administration Port, "Administration Channel" in Configuring and Managing WebLogic Server.
• For instructions on configuring an Administration Port, see Enabling the Domain-Wide Administration Port. a

To start all of the Managed Servers in a cluster standby mode:

1. Start the Administration Server for the domain.
2. In the Administration Console, expand the Clusters node in the left panel.
3. Click the cluster whose members you want to start.
4. Click the Start all servers in standby mode... link in the right panel.
5. When the Administration Console prompts you to confirm the command, click Yes.
6. As Node Manager starts each Managed Server, the status of the operation is displayed in the Transition Activity table. When an operation is complete for a Managed Server, TASK COMPLETED appears in the Status column.

Start all Servers

Use this command to start clustered Managed Servers with Node Manager.

Note: To start a Managed Server from the Administration Console using Node Manager, a Node Manager process must be running on each machine that hosts Managed Server in the cluster. For more information, refer to "Starting Node Manager" in Creating and Configuring WebLogic Servers and Domains.

To start all of the Managed Servers in a cluster:

1. Start the Administration Server for the domain.
2. In the Administration Console, expand the Clusters node in the left panel.
3. Click the cluster whose members you want to start.
4. Click the Start all servers... link in the right panel.
5. When the Administration Console prompts you to confirm the command, click Yes.
6. As Node Manager starts each Managed Server, the status of the operation is displayed in the Transition Activity table. When an operation is complete for a Managed Server, TASK COMPLETED appears in the Status column.

Resume all Servers

Use this command to resume cluster members in standby state with Node Manager.

Notes: To control a Managed Server from the Administration Console using Node Manager, a Node Manager process must be running on each machine that hosts Managed Server in the cluster. For more information, refer to "Starting Node Manager" in Creating and Configuring WebLogic Servers and Domains.

To resume clustered Managed Servers:

1. Start the Administration Server for the domain.
2. In the Administration Console, expand the Clusters node in the left panel.
3. Click the cluster whose members you want to resume.
4. Click the Resume all servers... link in the right panel.
5. When the Administration Console prompts you to confirm the command, click Yes.
6. As Node Manager resumes each Managed Server, the status of the operation is displayed in the Transition Activity table. When an operation is complete for a Managed Server, TASK COMPLETED appears in the Status column.

Graceful Shutdown of all Servers

Use this command to gracefully shutdown the Managed Servers in a cluster with Node Manager. During a graceful shutdown, WebLogic Server subsystems complete in-flight work and suspend themselves in an specific sequence and in a synchronized fashion. For details, see "Graceful Shutdown" in Creating and Configuring WebLogic Servers and Domains.

Note: To control a Managed Server from the Administration Console using Node Manager, a Node Manager process must be running on each machine that hosts Managed Server in the cluster. For more information, refer to "Starting Node Manager" in Creating and Configuring WebLogic Servers and Domains.

To gracefully shutdown clustered Managed Servers:

1. Start the Administration Server for the domain.
2. In the Administration Console, expand the Clusters node in the left panel.
3. Click the cluster whose members you want to shutdown.
4. Click the Graceful shutdown of all servers... link in the right panel.
5. When the Administration Console prompts you to confirm the command, click Yes.
6. The right panel displays shutdown settings.
   • If you want to drop all sessions, select Ignore Sessions During Shutdown.
   • If you want to set a timeout for the graceful shutdown to complete, enter the timeout period in seconds in the Graceful Shutdown Timeout box.

   Click Apply.

7. As the shutdown process proceeds, status is displayed in the Transition Activity table. When an operation is complete for a Managed Server, TASK COMPLETED appears in the Status column.

Force Shutdown of all Servers

Use this command to force shutdown the Managed Servers in a cluster with Node Manager.

Note: To control a Managed Server from the Administration Console using Node Manager, a Node Manager process must be running on each machine that hosts Managed Server in the cluster. For more information, refer to "Starting Node Manager" in Creating and Configuring WebLogic Servers and Domains.

To force shutdown clustered Managed Servers:

1. Start the Administration Server for the domain.
2. In the Administration Console, expand the Clusters node in the left panel.
3. Click the cluster whose members you want to shutdown.
4. Click the Force shutdown of all servers... link in the right panel.
5. When the Administration Console prompts you to confirm the command, click Yes.
6. As the shutdown process proceeds, status is displayed in the Transition Activity table. When an operation is complete for a Managed Server, TASK COMPLETED appears in the Status column.

Start/Stop a Server

Use the Start/Stop button in the Transition Activity table to start a Managed Server that is shutdown, or to gracefully shutdown a Managed Server that is running.

Note: To control a Managed Server from the Administration Console using Node Manager, a Node Manager process must be running on each machine that hosts Managed Server in the cluster. For more information, refer to "Starting Node Manager" in Creating and Configuring WebLogic Servers and Domains.

To start or stop a Managed Server in the current cluster:

1. Start the Administration Server for the domain.
2. In the Administration Console, expand the Clusters node in the left panel.
3. Click the cluster to which the Managed Server belongs.
4. The Transition Activity table lists the Managed Server in the cluster.
5. Click the Force shutdown of all servers... link in the right panel.
6. When the Administration Console prompts you to confirm the command, click Yes.
7. The right panel displays shutdown settings.
   • If you want to drop all sessions, select Ignore Sessions During Shutdown.
   • If you want to set a timeout for the graceful shutdown to complete, enter the timeout period in seconds in the Graceful Shutdown Timeout box.

   Click Apply.

8. As the shutdown process proceeds, status is displayed in the Transition Activity table. When an operation is complete for a Managed Server, TASK COMPLETED appears in the Status column.