Red Hat HPC cluster management is built around the concept of node groups. Node groups are a powerful template mechanism that allows the cluster administrator to define common shared characteristics among a group of nodes. Red Hat HPC ships with a default set of node groups for installer nodes, packaged installed compute nodes, diskless compute nodes and imaged compute nodes. The default node groups can be modified or new node groups can be created from the default node groups. All of the nodes in a node group share the following:

A typical HPC cluster is created from a single installer node and many compute nodes. Normally compute nodes are exactly the same as each other with a few exceptions, like the node name or other host specific configuration files. A node group for compute nodes makes it easy to configure and manage 1 or 100 nodes all from the same node group. The ngedit command is a graphical TUI (Text User Interface) run by the cluster administrator to create, delete and modify node groups. The ngedit tool modifies cluster information in the Red Hat HPC database and also automatically calls other tools and plugins to perform actions or update configuration. For example, modifying the set of packages associated with a node group in ngedit automatically calls cfm (configuration file manager) to synchronize all of the nodes in the cluster using yum to add and remove the new packages, while modifying the partitioning on the node group notifies the administrator that a re-install must be performed on the nodes in the node group in order to change the partitioning. The Red Hat HPC database keeps track of the node group state, thus several changes can be made to a node group simultaneously and the physical nodes in the group can be updated immediately or at a future time using the cfmsync command.

# ngedit