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Providing Open Source High-Availability Software for Linux and other OSes since 1999.

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This web page is no longer maintained. Information presented here exists only to avoid breaking historical links.
The Project stays maintained, and lives on: see the Linux-HA Reference Documentation.
To get rid of this notice, you may want to browse the old wiki instead.

1 February 2010 Hearbeat 3.0.2 released see the Release Notes

18 January 2009 Pacemaker 1.0.7 released see the Release Notes

16 November 2009 LINBIT new Heartbeat Steward see the Announcement

Last site update:
2019-12-11 14:33:38

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Project Goal

Provide a high availability (clustering) solution for Linux which promotes reliability, availability, and serviceability (RAS) through a community development effort.

What Is 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 (CRM) which has the task of starting and stopping the services (IP addresses, web servers, etc) that cluster will make highly available.

Heartbeat comes with a primitive resource manager, see haresources, however it is only capable of managing 2 nodes and does not detect resource-level failures.

A new resource manager which addressed these limitations and more was written for Heartbeat 2.0.0. However in 2007 the new resource manager was spun-off to become the Pacemaker project in order to better support additional cluster stacks (such as OpenAIS) and is no longer associated with the Linux-HA project.

The current stable series of Heartbeat is 2.99.x and can be obtained for many platforms (including CentOS, RHEL, Fedora, openSUSE and SLES) from


The Linux-HA project is a widely used and important component in many interesting High Availability solutions, and ranks as among the best HA software packages for any platform. We estimate that we currently have more than thirty thousand installations up in mission-critical uses in the real world since 1999. Interest in this project continues to grow. These web pages are average nearly 20000 hits per day, and we see more than 100 downloads of Heartbeat per day.

Heartbeat now ships as part of SUSE Linux, Mandriva Linux, Debian GNU/Linux, Ubuntu Linux, Red Flag Linux, and Gentoo Linux. Ultra Monkey, and several company's embedded systems are also based on it. Although this is called the Linux-HA project, the software is highly portable and runs on FreeBSD, Solaris, and OpenBSD, even on MacOS/X from time to time.

There have been many articles and several chapters in books written on this project and software. See the PressRoom for more details.

We include advanced integration with the DRBD real-time disk replication software, and also work well with the LVS (Linux Virtual Server) project. We expect to continue to collaborate with them in the future, since our goals are complementary.

Heartbeat is also a leading implementor of the Open Cluster Framework (OCF) standard and when combined with a resource manager like Pacemaker, is competitive with commercial systems similar to those described in D. H. Brown's 1998 or March 2000 analysis of RAS cluster features and functions. In fact Heartbeat + Pacemaker brings technologies and basic capabilities which match or exceed the capabilities of many commercial HA systems. Check it out, we think you'll be surprised.

We also have a page of reference sites (see SuccessStories) to provide a few real-life examples of how organizations both small and large use Heartbeat in production. Submissions for this page are actively encouraged.

The following types of applications are typical:

  • Database servers
  • ERP applications
  • Web servers
  • LVS director (load balancer) servers
  • Mail servers
  • Firewalls
  • File servers
  • DNS servers
  • DHCP servers
  • Proxy Caching servers
  • Custom applications

Heartbeat is used in virtually every market segment, industry, and organization size.

Project Timeline

  • Nov 15, 1998 - First alpha version available
  • Mar 27, 1999 - 0.2.0 First public release

    • Functional enough for a basic 2-node demo
    • Support for serial ports only.
  • May 9, 1999 - 0.3.0. Added support for UDP broadcast
  • Jun 30, 1999 - 0.4.0. New wire format (Name/value pairs)
  • Aug 14, 1999 - 0.4.2.
    • Implemented simple resource groups and start/stop notifications
    • Added a uniform resource model, with IP resources being only one kind.
  • October 1999 - website created
  • Oct 13, 2000 - 0.4.5. Added support for packet authentication
  • Apr 2, 2000 - 0.4.7. Robust error recovery code for packet retransmission.
  • Jun 30, 2000 - 0.4.8. Added a cluster test suite (CTS)
  • Nov 15, 2000 - 0.4.8g. First version to support STONITH, ping nodes,multiple resource parameters
  • Mar 16, 2001 - 0.4.9
    • First Heartbeat API and IPC library
    • Added support multicast media
  • Mar 16, 2001 - 0.4.9d released.

    • Added a membership/quorum subsystem (CCM)
    • Ability to monitor external connectivity (ipfail)
    • First version of BasicSanityCheck

  • Feb 19, 2003 - 1.0.1 Start of a new stable series

  • Sep 26, 2003 - 1.0.4. Last 1.0.x release
  • Dec 1, 2003 - Work begins on a modular, multi-node cluster resource manager (CRM) that also detects and recovers from resource-level failures
  • Feb 10, 2004 - 1.1.5. Last 1.1.x release
  • Feb 17, 2004 - 1.2.0. Start of a new stable series
  • Apr 16, 2004 - 1.3.0. New wire format (netstrings)
  • Oct 11, 2004 - 1.99.0. First beta version of the 'v2 CRM and LRM

  • Jul 30, 2005 - 2.0.0 First stable version of the new CRM

  • Aug 14, 2006 - 1.2.5. Last 1.2.x release
  • May 17, 2007 - 2.1.0 Start of a new stable series
  • Dec 7, 2007 - Announcement that the v2 CRM is now a separate project called Pacemaker which supports both the Heartbeat and OpenAIS cluster stacks.

  • Dec 21, 2007 - 2.1.3. Last release by Alan Robertson
  • Aug 18, 2008 - 2.1.4. The last release to include the CRM or stonithd
  • Aug 21, 2008 - 2.99.0 First version suitable for use with Pacemaker