HP XC System Software Installation Guide Version 3.1

Because you cannot assign the node_management role to any other node except the head node, the
avail_node_management role was developed to accomplish that task.
Never assign the avail_node_management role to the head node. Assign the avail_node_management
role only to the second node in an availability set to fail over the database server (dbserver) service.
F.3.3 Common Role
The common role is automatically assigned to all nodes, and it cannot be removed. This role runs services
that must be present on every node.
The configuration and management database names of the services provided by this role are as follows:
• Node data collection with the collectl utility (collectl)
• Hardware information gathering (gather_data)
• Environmental monitoring for the HP ProLiant DL585 server (hpasm)
• HPTC file system client (hptc_cluster_fs_client)
• IP firewall (iptables)
• IP firewall for IPv6 (ip6tables)
• Linux kernel crash dump (lkcd)
• Network adapter setup (network)
• Nagios remote plug-in execution agent (nrpe)
• Parallel distributed shell (pdsh)
• SLURM launch (munge)
• Disk monitoring on the HP Integrity rx1620 (smartd)
These services provide functionality that is required on all nodes and are fundamental to the proper
functioning of the cluster.
F.3.4 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 your 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.
F.3.5 Console_network Role
The console_network role enables you to map HP XC services with physical console requirements to
the appropriate nodes. By default, this role is assigned to the same set of nodes as the management_hub
role. In system installations in which only specially designated nodes can access the console network, you
can assign this role to those nodes instead, and the management and monitoring tools use only those
nodes.
You must assign the console_network role to nodes that have console access. Otherwise, Nagios plug-ins
that require console access will not collect data.
The configuration and management database names of the services provided by this role are as follows:
• Console management facility master (cmf)
• Console access (cpaccess)
F.3.6 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 configuration and management database 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.
F.3 Role Definitions 139