The Corosync Cluster Engine is a Group Communication System with additional
features for implementing high availability within applications. The project
provides four C Application Programming Interface features:

* A closed process group communication model with virtual synchrony guarantees
  for creating replicated state machines.
* A simple availability manager that restarts the application process when it
  has failed.
* A configuration and statistics in-memory database that provide the ability
  to set, retrieve, and receive change notifications of information.
* A quorum system that notifies applications when quorum is achieved or lost.

Corosync is used as a High Availability framework by projects such as Apache
Qpid and Pacemaker.