HP XC System Software Installation Guide Version 3.2

F Description of Node Roles, Services, and the Default
Configuration
This appendix addresses the following topics:
• “Default Node Role Assignments” (page 209)
• “Special Considerations for Modifying Default Node Role Assignments” (page 209)
• “Role Definitions” (page 210)
F.1 Default Node Role Assignments
Table F-1 lists the default role assignments. The default assignments are based on the number
of total nodes in the system.
Table F-1 Default Role Assignments Based on Number of Total Nodes
64 or More Nodes63 or Fewer Nodes
The following roles are assigned to the head node:
• common
• console_network
• disk_io
• external
• management_hub
• management_server
• node_management
The compute and resource_management roles are not assigned
to the head node.
The resource_management role is located on an exclusive node.
Service nodes that are configured with service roles that are not
essential for computation are not compute nodes. All other nodes
are compute nodes.
Compute nodes are assigned with one role: the compute role. No
other roles are configured on these nodes to keep them as free as
practical of services that are not needed for computation.
The following roles are assigned to the head
node:
• common
• compute
• console_network
• disk_io
• external
• management_hub
• management_server
• node_management
• resource_management
All nodes, including the head node, are
compute nodes.
F.2 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 G (page 215) describes how to modify and
verify node role assignments.
• “General Considerations” (page 209)
• “Special Considerations for Hardware Configurations with 63 or Fewer Nodes” (page 210)
• “Special Considerations for Hardware Configurations with 64 or More Nodes” (page 210)
• “Special Considerations for Improved Availability” (page 210)
F.2.1 General Considerations
Before deciding whether 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 execution host. If only one node has the resource_management role, both SLURM
F.1 Default Node Role Assignments 209