The CFREG provides a set of CF base product services that allows cluster applications to maintain cluster global data that must be consistent on all of the nodes in the cluster and must live through a clusterwide reboot.
Typical applications include cluster-aware configuration utilities that require the same configuration data to be present and consistent on all of the nodes in a cluster (for example, cluster volume management configuration data).
The data is maintained as named registry entries residing in a data file where each node in the cluster has a copy of the data file. The services will maintain the consistency of the data file throughout the cluster.
A user-level daemon (cfregd), runs on each node in the cluster, and is responsible for keeping the data file on the node where it is running synchronized with the rest of the cluster. The cfregd process will be the only process that ever modifies the data file. Only one synchronization daemon process will be allowed to run at a time on a node. If a daemon is started with an existing daemon running on the node, the started daemon will log messages that state that a daemon is already running and terminate itself. In such a case, all execution arguments for the second daemon will be ignored.
