Pacemaker is composed of four key components :

• CIB ( CLUSTER Information Base)
• CRMd ( Cluster Resource Management daemon)
• PEngine ( PE or Policy ENGINE)
• STONITHd

The CIB uses XML to represent both the cluster's configuration and current state of all resources in the cluster. The contents of the CIB are automatically kept in sync across the entire cluster and are used by the PEngine to compute the ideal state of the cluster and how it should be achieved.Pacemaker centralizes all cluster decision making by electing one of the CRMd INSTANCES to act as a master. Should the elected CRMd process (or the node it is on) fail… a new one is quickly established.

STONITH is an acronym for Shoot-The-Other-Node-In-The-Head and is USUALLY implemented with a remote power switch. In Pacemaker, STONITH devices are modeled as resources (and configured in the CIB) to enable them to be EASILY monitored for failure.

Pacemaker is composed of four key components :

The CIB uses XML to represent both the cluster's configuration and current state of all resources in the cluster. The contents of the CIB are automatically kept in sync across the entire cluster and are used by the PEngine to compute the ideal state of the cluster and how it should be achieved.Pacemaker centralizes all cluster decision making by electing one of the CRMd instances to act as a master. Should the elected CRMd process (or the node it is on) fail… a new one is quickly established.

STONITH is an acronym for Shoot-The-Other-Node-In-The-Head and is usually implemented with a remote power switch. In Pacemaker, STONITH devices are modeled as resources (and configured in the CIB) to enable them to be easily monitored for failure.