About ClusterLabs

Open-source high-availability started with the release of Heartbeat by Bell Labs' Alan Robertson. It supported two-node clusters and monitoring of node-level failures. The community that arose around the development of Heartbeat and related software became known as High Availability Linux, or Linux-HA.

Linux-HA's Heartbeat added a simple resource manager to detect resource-level failures.

SUSE hired Alan Robertson and began supporting Linux-HA.

Separately, the Mission Critical Linux distribution released its Kimberlite high-availability failover project under an open-source license. It supported 2-node clusters and shared storage.

Linux-HA developers started the Open Cluster Framework (OCF) to develop a set of generic high-availability APIs that could be implemented for any underlying clustering software.

Separately, the Service Availability (SA) Forum, a consortium of communication and computing companies, was formed to develop specifications for carrier-grade and mission-critical systems using off-the-shelf technology.

Red Hat Enterprise Linux (RHEL) 2.1 included the Red Hat Cluster Suite (RHCS), based around Kimberlite.

SUSE hired Andrew Beekhof to improve Linux-HA's cluster resource manager as a distinct layer on top of the main Heartbeat code.

The SA Forum defined the Application Interface Specification (AIS), a set of APIs for high-availability features. Open Source Development Labs released the OpenAIS implementation the same year.

Developers from Red Hat and SUSE met for the first HA Summit, in Prague, Czechia, to discuss future directions for the various projects in an effort to reduce duplication.

Linux-HA's Heartbeat 2 was released with support for multiple nodes and its new, more feature-rich cluster resource manager.

Red Hat's RHCS was reorganized to provide the CMAN cluster manager, with cluster membership and messaging capabilities, and the rgmanager resource manager.

Red Hat's RHCS supported using CMAN as a plugin for OpenAIS, to combine their functionalities.

Heartbeat spun off two projects: its cluster resource manager became the Pacemaker project, and its core libraries became the cluster-glue project. Pacemaker 0.6.0 could use either Heartbeat or OpenAIS as its cluster layer. The ClusterLabs.org domain was registered for Pacemaker's website.

The open-source HA community held its second HA Summit.

OpenAIS split into two parts: OpenAIS itself retained solely the AIS APIs and was deprecated, while Corosync provided the actual functionality of cluster membership and messaging.

SUSE's SLES 11 included Pacemaker with OpenAIS instead of Heartbeat. It also included the crm shell as a high-level command-line management interface.

Pacemaker 1.1.3 supported CMAN and Corosync as alternative cluster layers.

RHEL 6.0's RHCS, rebranded as the RHEL High-Availability Add-On, included Corosync and CMAN.

RHEL 6.5's HA Add-On supported Pacemaker as an alternative to rgmanager, and introduced pcs as a high-level command-line management interface.

By the time of the third HA Summit in Brno, Czechia, Heartbeat and CMAN had ceased active development, and the community had converged on a cluster stack utilizing Corosync and Pacemaker.

Participants voted to use the ClusterLabs name as an umbrella for the surviving projects, to improve cooperation and raise awareness. Websites, mailing lists, and source repositories began to be consolidated under ClusterLabs.

The newly renamed ClusterLabs Summit was held in Nuremberg, Germany.

Another ClusterLabs Summit was held in Brno, Czechia, just days before the COVID-19 pandemic shut down global travel.