The Red Hat Cluster Manager software was originally based on the open source Kimberlite (http://oss.missioncriticallinux.com/kimberlite/) cluster project, which was developed by Mission Critical Linux, Inc.
Subsequent to its inception based on Kimberlite, developers at Red Hat have made a large number of enhancements and modifications. The following is a non-comprehensive list highlighting some of these enhancements.
Packaging and integration into the Red Hat installation paradigm to simplify the end user's experience.
Addition of support for multiple cluster members.
Addition of support for high availability NFS services.
Addition of support for high availability Samba services.
Addition of the Cluster Configuration Tool, a graphical configuration tool.
Addition of the Cluster Status Tool, a graphical monitoring and administration tool.
Addition of support for failover domains.
Addition of support for Red Hat GFS, including the GFS Setup Druid and the LOCK_GULM fencing driver.
Addition of support for using watchdog timers as a data integrity provision.
Addition of service monitoring which automatically restart a failed application.
Rewrite of the service manager to facilitate additional cluster-wide operations.
A set of miscellaneous bug fixes.
The Red Hat Cluster Manager software incorporates STONITH compliant power switch modules from the Linux-HA project; refer to http://www.linux-ha.org/stonith/.