HP XC System Software Installation Guide Version 3.0

• Parallel distributed shell (pdsh)
• SLURM launch (munge)
These services provide functionality that is required on all nodes and are fundamental to the proper functioning
of the cluster.
Compute Role
Jobs are distributed to and run on nodes with the compute role. This role provides the services required for
the node to be an allocated resource of the SLURM central control service (slurmcd).
On systems with fewer than 63 total nodes, this role is assigned to all nodes; on large-scale systems with
more than 64 nodes, this role is assigned exclusively to nodes with no other roles assigned.
Any node with this role may be called upon to execute jobs scheduled by the users. Nodes with this role
are also often called compute nodes.
It is the administrator's responsibility to remove this role on a node if it is not wanted or required.
To enable monitoring of the nodes, run the Nagios remote plug-in execution agent on nodes with the compute
role
Disk_io Role
Nodes with the disk_io role provide access to storage and file systems mounted locally on the node. This
role can be located on any node that provides local file system access to all nodes using NFS. Assign this
role to any node that is exporting SAN storage.
The management database name for the NFS Server service supplied by this role is nfs_server.
Nodes with this role normally reside in the utility cabinet of the cluster and have the most direct access to
storage.
You can assign other roles to a node with this role. However, you must be careful not to overload the node
so it can provide adequate NFS service.
External Role
The external role supplies the NAT server service, which does network address translation within the
cluster. This enables applications to access nodes that do not have an external network connection. The
management database name of the service supplied by this role is nat.
Assign this role only to nodes that have an external network connection configured.
The system can have multiple nodes defined with the external role, supplying multiple NAT servers to
ease network traffic congestion.
Applications have no need to be aware of the actual internal IP address of a compute node because a NAT
server node handles all network requests.
Login Role
Nodes with the login role accept login sessions of users. A user can submit jobs from the command line
on a node with a login role. The jobs then are distributed among compute nodes to process the job. Nodes
with this role should have an external network connection configured.
The login role supplies a node with the LVS Director service, which handles the placement of user login
sessions on login nodes when a user logs in to the cluster alias.
The management database name for the service supplied by this role is lvs.
Management Hub Role
A node with the management hub role is an aggregation point for management activities.
The management database names of the services provided by this role are as follows:
• Console management facility master (cmf)
• Nagios monitor (nagios_monitor)
Role Definitions 93