Chapter 9. Clustering

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.
Refer to Section 19.5, “Clustering and High Availability” for a list of documents available for Red Hat Enterprise Linux 7 providing information about configuration and management of Red Hat High Availability Add-On.

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.