Special Considerations for Modifying Default Node Role Assignments

This section presents information you need to consider before accepting the default role assignments made by the cluster_config utility. After reading this information, you may decide to modify the default assignments. Appendix F describes how to modify and verify node role assignments.

General Considerations

Before deciding whether or not you want to accept the default configuration, consider the following:

By default only one node is configured with the resource_management role. The resource_management role consists of one or more SLURM controller daemons and the LSF XC execution host. If only one node has the resource_management role, both SLURM and LSF controller daemons run on that node, and no failover of these components is possible.
HP recommends that you configure at least two nodes with the resource_management role to distribute the work of these components and provide for failover configuration.
If you expect LSF to be accessible from outside the HP XC system, all nodes with the resource_management role must also be configured with the external role and have the appropriate hardware and wiring to directly access the external network.
If standard LSF is selected, the node or nodes with the resource_management role are configured first, and the first node listed is the LSF Master Host.
You must assign the disk_io role to any node that is exporting SAN storage.
No nodes are configured with the login role. Assigning a login role to a node enables the LVS director service. You must assign a login role to each node on which you expect users to be able to log in and use the system.
No nodes are configured with the nis_server role. Assigning a nis_server role to a node establishes the node as a NIS slave server. Any node assigned with the nis_server role must also have an external network connection defined.
You must assign an external role to any node that has an external network connection configured.

Considerations for Systems with 63 or Fewer Nodes

Before deciding whether or not you want to accept the default configuration for systems with 63 or fewer nodes, consider that a compute role is assigned to the head node by default. Thus, LSF users submit jobs that run on the head node and obtain less than optimal performance if interactive users are also on the head node. You may want to consider removing the compute role from the head node to prevent it from being configured as a SLURM compute node.

Considerations for Systems with 64 or More Nodes

Before deciding whether or not you want to accept the default configuration provided for systems with 64 or more nodes, consider that the cluster is optimized for computation by default; that is, compute nodes have no additional services on them. Therefore, consider whether you want more compute nodes overall at the expense of impact to other services on those nodes.

Special Considerations for Modifying Default Node Role Assignments

Technical documentation

» Table of Contents

» Glossary

» Index

General Considerations

Considerations for Systems with 63 or Fewer Nodes

Considerations for Systems with 64 or More Nodes