Linux-HA ======== Providing Open Source High-Availability Software for Linux and other Platforms since 1999 The Linux-HA project maintains a set of building blocks for high availability cluster systems, including * a cluster messaging layer (heartbeat, see below), * a huge number of resource agents for a variety of applications, * a plumbing library and error reporting toolkit (aka cluster-glue) http://linux-ha.org/wiki/Main_Page http://en.wikipedia.org/wiki/Computer_cluster http://linux-ha.org/wiki/Heartbeat http://linux-ha.org/wiki/Resource_Agents http://linux-ha.org/wiki/Cluster_Glue Historical note =============== Since up to release 2.1.4 the messaging layer (Heartbeat proper), the Local Resource Manager, "plumbing" infrastructure and STONITH (now known as Cluster Glue), the Resource Agents, and the Cluster Resource Manager (now Pacemaker) were all part of a single package named heartbeat, the name was often applied to the Linux-HA project as a whole. This generalization is no longer accurate, the name heartbeat should thus be used for the messaging layer exclusively. Heartbeat ========= Heartbeat is a daemon that provides cluster infrastructure (communication and membership) services to its clients. This allows clients to know about the presence (or disappearance!) of peer processes on other machines and to easily exchange messages with them. In order to be useful to users, the Heartbeat daemon needs to be combined with a cluster resource manager. A cluster resource manager (CRM) has the task of starting and stopping the services (IP addresses, web servers, etc.) which the cluster will make highly available. Heartbeat still comes with an integrated primitive resource manager, which basically is just a shell script. This is also referred to as "v1 style" or "haresources style" configuration. The haresources mode of operation is deprecated. If you miss it, please see http://www.planet-ha.org/#Configuring+Heartbeat+v1+Was+So+Simple Pacemaker is the preferred cluster resource manager for clusters based on the Heartbeat infrastructure layer. Reference Documentation ======================= To get you started, for further information, reference documentation and setup recommendations, refer to http://linux-ha.org/wiki/Documentation http://clusterlabs.org/wiki/Documentation Help and Support ================ For community support, mailing lists, IRC channels, and other ways to report problems and get them solved, see http://linux-ha.org/wiki/Support See Also ======== Csync2 an easy way to keep a bunch of infrequently updated files in sync over groups of nodes. http://oss.linbit.com/csync2/ DRBD a nicely integrated (with Pacemaker) replication solution, you won't need shared disks to do HA-clustering. http://www.drbd.org