The Compute Nodes

The compute nodes are the power of the cluster, as they are used for the calculations. A copy of the distributed processes will run on each requested compute node. Compute nodes are trashable, replaceable, and reconfigurable; partial downtime does not affect the overall availability of the cluster.

"Compute" Nodes and "Non-compute" Nodes

In a cluster environment there are two types of nodes: (1) those that contribute directly to computing and (2) those that do not. For example, a NAS will be a "non-compute" node, because although it still requires elements from the head node, it will not join the group of hosts that performs the actual jobs. Another good example will be a managed switch, which still requires an IP address to be assigned via DHCP, but does not run jobs.

AutoYaST

AutoYaST is a tool provided by SLES to ease provisioning. The installation of a compute node is based on this tool, which allows complete configurability of the software stack on the compute nodes.

AutoYaST Profiles

An AutoYaST profile defines the whole setup of a node, from packages to partitioning and hardware options. You can edit the profile with the AutoYaST profile editor prior to the compute node install. Every time you modify a profile for a node that has already been installed, you must reprovision the node for the changes to take effect.

Moab Cluster Builder Profiles

Profiles in Moab Cluster Builder are a logical extension of AutoYaST profiles. In the Moab Cluster Builder profiles, more information is included about the type of OS that is installed on the node, the architecture of the machine, and the installation sources for provisioning.

Default Profiles

Two default profiles—compute and non-compute—are defined to speed up simple deployments.

Compute

The "compute" profile defines a default SLES installation for the targeted machine that is configured to run jobs as a TORQUE mom.

Non-compute

The "non-compute" profile defines a default netwrok host that does not require any installation and does not join the TORQUE host pool.

Install Sources

An install source can be a DVD, an ISO file, or a directory, containing the installation files for an OS. (The default DVD already contains the sources for SLES10 SP1.) Each profile is based on a source, and a single source can be shared by multiple profiles.