The Linux-HA (High-Availability Linux) project provides a
high-availability
High availability (HA) is a characteristic of a system that aims to ensure an agreed level of operational performance, usually uptime, for a higher than normal period.
There is now more dependence on these systems as a result of modernization. ...
(
clustering) solution for
Linux
Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...
,
FreeBSD
FreeBSD is a free-software Unix-like operating system descended from the Berkeley Software Distribution (BSD). The first version was released in 1993 developed from 386BSD, one of the first fully functional and free Unix clones on affordable ...
,
OpenBSD
OpenBSD is a security-focused operating system, security-focused, free software, Unix-like operating system based on the Berkeley Software Distribution (BSD). Theo de Raadt created OpenBSD in 1995 by fork (software development), forking NetBSD ...
,
Solaris
Solaris is the Latin word for sun.
It may refer to:
Arts and entertainment Literature, television and film
* ''Solaris'' (novel), a 1961 science fiction novel by Stanisław Lem
** ''Solaris'' (1968 film), directed by Boris Nirenburg
** ''Sol ...
and
Mac OS X
macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...
which promotes
reliability
Reliability, reliable, or unreliable may refer to:
Science, technology, and mathematics Computing
* Data reliability (disambiguation), a property of some disk arrays in computer storage
* Reliability (computer networking), a category used to des ...
,
availability
In reliability engineering, the term availability has the following meanings:
* The degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at ...
, and
serviceability (RAS).
[Alan Robertson ''The Evolution of The LinuxHA project''. IBM Linux Technology Center, 201]
/ref>
The project's main software product is Heartbeat, a GNU General Public License, GPL-licensed portable cluster management program for high-availability clustering. Its most important features are:
* no fixed maximum number of nodes - Heartbeat can be used to build large clusters as well as very simple ones
* resource monitoring: resources can be automatically restarted or moved to another node on failure
* fencing mechanism to remove failed nodes from the cluster
* sophisticated policy-based resource management, resource inter-dependencies and constraints
* time-based rules allow for different policies depending on time
* several resource scripts (for Apache
The Apache ( ) are several Southern Athabaskan language-speaking peoples of the Southwestern United States, Southwest, the Southern Plains and Northern Mexico. They are linguistically related to the Navajo. They migrated from the Athabascan ho ...
, IBM Db2, Oracle
An oracle is a person or thing considered to provide insight, wise counsel or prophetic predictions, most notably including precognition of the future, inspired by deities. If done through occultic means, it is a form of divination.
Descript ...
, PostgreSQL
PostgreSQL ( ) also known as Postgres, is a free and open-source software, free and open-source relational database management system (RDBMS) emphasizing extensibility and SQL compliance. PostgreSQL features transaction processing, transactions ...
etc.) included
* Graphical user interface
A graphical user interface, or GUI, is a form of user interface that allows user (computing), users to human–computer interaction, interact with electronic devices through Graphics, graphical icon (computing), icons and visual indicators such ...
(GUI) for configuring, controlling and monitoring resources and nodes
History
The project originated from a mailing list started in November 1997. Eventually Harald Milz wrote an odd sort of Linux-HA HOWTO. Unlike most HOWTOs, this was not about how to configure or use existing software, it was a collection of HA techniques which one could use if one were to write HA software for Linux.
Alan Robertson was inspired by this description and thought that he could perhaps write some of the software for the project to act as a sort of initial seed crystal to help jump start the project. He got this initial software running on 18 March 1998. He created the first web site for the project on 19 October 1998, and the first version of the software was released on 15 November 1998. The first production customer of the software was Rudy Pawul of ISO-NE. The ISO-NE web site went into production in the second half of 1999.
At this point, the project was limited to two nodes and very simple takeover semantics, and no resource monitoring.Pacemaker
A pacemaker, also known as an artificial cardiac pacemaker, is an implanted medical device that generates electrical pulses delivered by electrodes to one or more of the chambers of the heart. Each pulse causes the targeted chamber(s) to co ...
, and the resource agents and other "glue" infrastructure were moved to separate packages. Thus with the version 3 series, the name ''Heartbeat'' should be used for the cluster messaging layer only.
See also
* Open Cluster Framework
Open Cluster Framework (OCF) is a set of standards for computer clustering.
The project started as a working group of the Free Standards Group, now part of the Linux Foundation. Original supporters included several computing companies and groups, ...
* Corosync Cluster Engine
The Corosync Cluster Engine is an open source implementation of the Totem Single Ring Ordering and Membership protocol. It was originally derived from the OpenAIS project and licensed under the new BSD License. The mission of the Corosync effor ...
Notes
References
*
*
External links
*
archives of Linux-HA's main mailing list
{{DEFAULTSORT:Linux-Ha
Free system software
Parallel computing
High-availability cluster computing
1999 software