1.2. What Is Pacemaker?

Pacemaker is a cluster resource manager. It achieves maximum availability for your cluster services (aka. resources) by detecting and recovering from node and resource-level failures by making use of the messaging and membership capabilities provided by your preferred cluster infrastructure (either Corosync or Heartbeat).

Pacemaker's key features include:

Detection and recovery of node and service-level failures
Storage agnostic, no requirement for shared storage
Resource agnostic, anything that can be scripted can be clustered
Supports STONITH for ensuring data integrity
Supports large and small clusters
Supports both quorate and resource driven clusters
Supports practically any redundancy configuration
Automatically replicated configuration that can be updated from any node
Ability to specify cluster-wide service ordering, colocation and anti-colocation
Support for advanced services type
- Clones: for services which need to be active on multiple nodes
- Multi-state: for services with multiple modes (eg. master/slave, primary/secondary)
Unified, scriptable, cluster shell