HPC clusters are built from individual compute nodes and all of these nodes must have copies of common system files such as /etc/passwd, /etc/shadow, /etc/group and others.

Red Hat HPC contains a file synchronization service called CFM (Configuration File Manager).

CFM runs on each compute node in the cluster and when new files are available on the installer node a message is sent to all of the nodes notifying them that files are available. Each compute node connects to the installer node and copies the new files using the HTTP protocol. All files to be synchronized by CFM are located in the directory tree /etc/cfm/<node group> as can be seen in the following screenshot:

In the screenshot above /etc/cfm directory contains several node group directories such as compute-diskless and compute-rhel. In each of those directories is a directory tree where the /etc/cfm/<node group> directory represents the root of the tree. The /etc/cfm/compute-rhel/etc directory contains several files or symbolic links to system files.

Creating symbolic links for the files in CFM allows the compute nodes to be automatically synchronized with system files on the installer node. /etc/passwd and /etc/shadow are two examples where symlinks are used.

Adding files to cfm is simple. Create all of the directories and subdirectories for the file then place the file in the appropriate location.

Existing files can also have a <filename>.append file. The contents of a <filename>.append file are automatically appended to the existing <filename> file on all nodes in the node group.

Use the cfmsync command to notify all of the nodes in all node groups or nodes in a single node group. For example:

			
# cfmsync –f –n compute-rhel

Synchronizes all files in the compute-rhel node group.

# cfmsync –f

Synchronizes all files in all node groups

For more information on cfmsync view the man pages.