Red Hat RH00386F3, Lisenssi

Red Hat's High Availability add-on provides on-demand failover services between nodes within a cluster, making applications highly available. The High Availability add-on supports up to 16 nodes and may be configured for many applications, that use customizable agents, as well as for virtual guests. The High Availability add-on also features failover support for off-the-shelf applications, like Apache, MySQL, and PostgreSQL. When using the High Availability add-on, a highly available service can fail over from one node to another with no apparent interruption to cluster clients. The High Availability add-on also ensures data integrity, when one cluster node takes over control of a service from another cluster node. It achieves this by promptly evicting nodes from the cluster, that are deemed to be faulty using a method called "fencing", that prevents data corruption.