HP XC System Software Installation Guide Version 3.0

• 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.
Role Definitions
A node role is defined by the services provided by the node. The role is an abstraction that combines one
or more services into a group. Roles provide a convenient way of installing services on a node. Node roles,
listed alphabetically, are characterized as follows:
• Common Role (page 92)
• Compute Role (page 93)
• Disk_io Role (page 93)
• External Role (page 93)
• Login Role (page 93)
• Management Hub Role (page 93)
• Management Server Role (page 94)
• NIS Server Role (page 94)
• Node Management Role (page 94)
• Resource Management Role (page 95)
You can define multiple roles on any node. The head node, in particular, can have all of these roles if you
are setting up a small cluster.
If you need more information about services and node roles, see the HP XC System Software Administration
Guide .
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 management database names of the services provided by this role are as follows:
• 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)
• Linux kernel crash dump (lkcd)
• Network adapter setup (network)
• Nagios remote plug-in execution agent (nrpe)
92 Node Roles, Services, and the Default Configuration