Change the Role of a Cluster Node

Updated: January 2011

Applies To: Windows HPC Server 2008 R2

This topic describes how to change the role of a node in a Windows HPC Server 2008 R2 cluster after the node has been deployed. For example, you might want to use some of the Windows Communication Foundation (WCF) broker nodes in the cluster as compute nodes instead, or you may need to increase the number of WCF broker nodes to run service-oriented architecture jobs.

Depending on the role of the current node and the role that you want to change to, use one of the following procedures to change the role of a node:

• Enable or disable an installed role on the node

• Redeploy the node

Enable or disable an installed role on the node

You can use HPC Cluster Manager to disable or enable one of the installed node roles on a head node or a broker node. You can apply the Change Role action or, alternatively, run the Set-HpcNode PowerShell cmdlet using the –Role parameter.

The following table shows the node roles that are installed on the head node and on each broker node.

Node	Installed roles
Head node	Head node WCF broker node Compute node Note You cannot disable the head node role.
Broker node	WCF broker node Compute node Note At least one node role must be enabled.

Important

You cannot use the Change Role action to change the role of a compute node or a workstation node. Each compute node and each workstation node has only the compute node role installed. After you change the role of a WCF broker node to a compute node, you can re-enable the WCF role on the node by using the Change Role action. Enabling an additional role on a node can adversely affect the performance of the node. For more information about the node roles that are installed and enabled by default on the cluster nodes, see Understanding Node Roles.

To change the role of a node using the Change Role action

1. On the head node of your HPC cluster, open HPC Cluster Manager. Click Start, point to All Programs, click Microsoft HPC Pack 2008 R2, and then click HPC Cluster Manager.

2. In Node Management, in the Views pane, select a head node or a broker node.

3. If the node is not already in the Offline state, right-click your selection, and then click Take Offline. If a job is currently running on the node, the node enters the Draining state.

4. After the node is in the Offline state, right-click your selection, and then click Change Role.

5. In the Change Node Roles dialog box, select the node role or the roles that you want to be enabled on the node, and then click OK.

6. Right-click the node, and then click Bring Online.

Redeploy the node

In some cases, to change the role of a node, you cannot use the Change Role action - for example, to change the role of a compute node to a WCF broker node. To do this, you must redeploy the node using one of the standard methods that are available in Windows HPC Server 2008 R2.

To redeploy a compute node as a WCF broker node

1. In Node Management, first take the node to the Offline state. If a job is currently running on the node, it enters the Draining state.

2. Delete the node from the Windows HPC cluster, and then reinstall the node using an appropriate node template.

   -OR-

   Reimage the node by assigning a node template that contains a broker node image.

Important
If you reinstall the node without first deleting the node from the cluster, the node might still appear in HPC Cluster Manager as a compute node. You can manually correct this by synchronizing the node with the head node. This process causes the head node to rediscover the node whose role has changed.

To synchronize a node with the head node

1. In Node Management, first take the node to the Offline state. If a job is currently running on the node, it enters the Draining state.

2. Assign a node template (which does not contain an operating system image) to the node.

3. After the node role is changed, right-click the node, and then click Bring Online.