In this section, we will delve into the configuration and management of OpenVMS clusters. Clustering is a powerful feature of OpenVMS that allows multiple systems to work together, providing high availability, load balancing, and scalability. This module will cover the essential concepts, configuration steps, and management practices for OpenVMS clusters.

1. Cluster: A group of interconnected computers that work together as a single system.
2. Node: An individual computer within a cluster.
3. Interconnect: The communication link between nodes in a cluster.
4. Quorum: The minimum number of nodes that must be operational for the cluster to function.
5. Cluster Alias: A single network name that represents the entire cluster.

• High Availability: Ensures that services remain available even if one or more nodes fail.
• Load Balancing: Distributes workloads across multiple nodes to optimize performance.
• Scalability: Allows the addition of more nodes to handle increased workloads.

Before configuring a cluster, it's essential to plan the following:

• Cluster Size: Determine the number of nodes.
• Interconnect Type: Choose the communication method (e.g., Ethernet, FDDI).
• Quorum Strategy: Decide on the quorum configuration to ensure cluster stability.

Ensure that all nodes are properly connected via the chosen interconnect. Verify that all hardware components are compatible with OpenVMS clustering.

Install OpenVMS on each node in the cluster. Ensure that all nodes are running the same version of OpenVMS.

a. Enabling Cluster Services

On each node, enable the cluster services by editing the SYS$MANAGER:SYLOGICALS.COM file:

b. Configuring the Cluster Interconnect

Edit the SYS$MANAGER:CLUSTER_CONFIG.COM file to configure the interconnect:

Follow the prompts to specify the interconnect type and parameters.

c. Setting Up Quorum

Configure the quorum settings in the SYS$MANAGER:QUORUM_CONFIG.COM file:

Specify the quorum disk and the quorum value.

Start the cluster services on each node:

Verify that all nodes are communicating and that the cluster is operational.

Use the following commands to monitor the health and status of the cluster:

• SHOW CLUSTER: Displays the status of all nodes in the cluster.

  $ SHOW CLUSTER
  

• MONITOR CLUSTER: Provides real-time monitoring of cluster performance.

  $ MONITOR CLUSTER
  

Adding a Node

1. Install OpenVMS on the new node.
2. Configure the cluster software as described above.
3. Start the cluster services on the new node.

Removing a Node

1. Shut down the node to be removed.
2. Update the cluster configuration to remove references to the node.
3. Restart the cluster services on the remaining nodes.

• Disk Management: Ensure that shared disks are accessible to all nodes.
• Network Management: Configure network settings to support cluster communication.
• Security Management: Implement security measures to protect cluster resources.

Objective: Configure a two-node OpenVMS cluster.

Steps:

1. Install OpenVMS on both nodes.
2. Enable cluster services on both nodes.
3. Configure the interconnect and quorum settings.
4. Start the cluster services and verify the cluster status.

Solution:

1. Install OpenVMS:

   • Follow the OpenVMS installation guide for each node.

2. Enable Cluster Services:

   • On Node1:

     $ DEFINE/SYSTEM/EXECUTIVE SYS$NODE_NODE1 "NODE1"
     $ DEFINE/SYSTEM/EXECUTIVE SYS$CLUSTER "MYCLUSTER"
     

   • On Node2:

     $ DEFINE/SYSTEM/EXECUTIVE SYS$NODE_NODE2 "NODE2"
     $ DEFINE/SYSTEM/EXECUTIVE SYS$CLUSTER "MYCLUSTER"
     

3. Configure Interconnect and Quorum:

   • On both nodes:

     $ @SYS$MANAGER:CLUSTER_CONFIG.COM
     

     Follow the prompts to configure the interconnect.

     $ @SYS$MANAGER:QUORUM_CONFIG.COM
     

     Specify the quorum disk and value.

4. Start Cluster Services:

   • On both nodes:

     $ @SYS$STARTUP:STARTUP.COM
     

5. Verify Cluster Status:

   • On either node:

     $ SHOW CLUSTER
     

In this section, we covered the essential steps for configuring and managing an OpenVMS cluster. We discussed the key concepts, benefits, and practical steps involved in setting up a cluster. By following the provided exercise, you should now have a basic understanding of how to configure a simple OpenVMS cluster. In the next section, we will explore cluster communication in more detail.