Clusters are multiple computers (nodes) working together to increase reliability, scalability, and availability to critical production services. High Availability using Red Hat Enterprise Linux 7 can be deployed in a variety of configurations to suit varying needs for performance, high-availability, load balancing, and file sharing.
9.1. Pacemaker Cluster Manager
Red Hat Enterprise Linux 7 replaces rgmanager with Pacemaker for managing cluster resources and recovering from node failures.
Some of the benefits of Pacemaker include:
Automatic synchronization and versioning of the resource configuration;
A flexible resource and fencing model that can more closely match the user's environment;
Fencing can be used to recover from resource-level failures;
Time-based configuration options;
The ability to run the same resource on multiple nodes. For example, a web server or cluster file system;
The ability to run the same resource on multiple nodes in one of two different modes. For example, a sync source and target;
Pacemaker does not require a distributed lock manager;
Configurable behavior when quorum is lost or multiple partitions are formed.