We support many deployment scenarios, from the simplest 2-node standby cluster to a 32-node active/active configuration. We can also dramatically reduce hardware costs by allowing several active/passive clusters to be combined and share a common backup node.
We monitor the system for both hardware and software failures. In the event of a failure, we will automatically recover your application and make sure it is available from one of the remaning machines in the cluster.
After a failure, we use advanced algorithms to quickly determine the optimum locations for services based on relative node preferences and/or requirements to run with other cluster services (we call these "constraints").
At its core, a cluster is a distributed finite state machine capable of co-ordinating the startup and recovery of inter-related services across a set of machines.
System HA is possible without a cluster manager, but you save many headaches using one anyway
Even a distributed and/or replicated application that is able to survive the failure of one or more components can benefit from a higher level cluster:
While SYS-V init replacements like systemd can provide deterministic recovery of a complex stack of services, the recovery is limited to one machine and lacks the context of what is happening on other machines - context that is crucial to determine the difference between a local failure, clean startup or recovery after a total site failure.
The ClusterLabs stack, incorporating Corosync and Pacemaker defines an Open Source, High Availability cluster offering suitable for both small and large deployments.
"The definitive open-source high-availability stack for the Linux platform builds upon the Pacemaker cluster resource manager."
-- LINUX Journal, "Ahead of the Pack: the Pacemaker High-Availability Stack"
A Pacemaker stack is built on five core components:
We describe each of these in more detail as well as other optional components such as CLIs and GUIs.
Pacemaker has been around since 2004 and is primarily a collaborative effort between Red Hat and SUSE, however we also receive considerable help and support from the folks at LinBit and the community in general.
Corosync also began life in 2004 but was then part of the OpenAIS project. It is primarily a Red Hat initiative, with considerable help and support from the folks in the community.
The core ClusterLabs team is made up of full-time developers from Australia, Austria, Canada, China, Czech Repulic, England, Germany, Sweden and the USA. Contributions to the code or documentation are always welcome.
The ClusterLabs stack ships with most modern enterprise distributions and has been deployed in many critical environments including Deutsche Flugsicherung GmbH (DFS) which uses Pacemaker to ensure its air traffic control systems are always available.
- The ClusterLabs wiki has + The ClusterLabs wiki has how-to's, tips, and other information that doesn't make it into the project manuals.
+ A good first step is always to check out + the FAQ + and documentation. Otherwise, many + members of the community hang out + on IRC + and are happy to answer questions. We are spread out over + many timezones though (and have day jobs), so you may need + to be patient when waiting for a reply. +
-- A good first step is always to check out - the FAQ - and documentation. Otherwise, many - members of the community hang out - on IRC - and are happy to answer questions. We are spread out over - many timezones though (and have day jobs), so you may need - to be patient when waiting for a reply. -
++ Extended or complex issues might be better sent to the + relevant mailing list + (you'll need to subscribe in order to send messages). +
-- Extended or complex issues might be better sent to the - relevant mailing list - (you'll need to subscribe in order to send messages). -
++ People new to the project, or Open Source generally, are + encouraged to + read Getting + Answers by Mike Ash from Rogue Amoeba. It provides + some very good tips on effective communication with groups + such as this one. Following the advice it contains will + greatly increase the chance of a quick and helpful reply. +
-- People new to the project, or Open Source generally, are - encouraged to - read Getting - Answers by Mike Ash from Rogue Amoeba. It provides - some very good tips on effective communication with groups - such as this one. Following the advice it contains will - greatly increase the chance of a quick and helpful reply. -
++ Bugs and other problems can also be reported + via Bugzilla. +
-Bugs and other problems can also be reported - via Bugzilla. -
-- Or if you already know the - solution, submit - a patch against - our GitHub - repository. -
++ Or if you already know the + solution, submit + a patch against + our GitHub + repository. +
-- The development of most of the ClusterLabs-related projects take place as part of - the ClusterLabs organization at Github, - and the source code and issue trackers for these projects can be found there. -
++ The development of most of the ClusterLabs-related projects take place as part of + the ClusterLabs organization at Github, + and the source code and issue trackers for these projects can be found there. +
-- If you find this project useful, you may want to consider supporting its future development. - There are a number of ways to support the project (in no particular order): -
-- Thank you for using Pacemaker -
++ If you find this project useful, you may want to consider supporting its future development. + There are a number of ways to support the project (in no particular order): +
++ Thank you for using Pacemaker +
-- Does your company provide Pacemaker training or - support? Let - us know! -
++ Does your company provide Pacemaker training or + support? Let + us know! +
-Most of the documentation listed here was generated from the Pacemaker sources.
If you're new to Pacemaker or clustering in general, the best place to start is Clusters from Scratch, which walks you step-by-step through the installation and configuration of a high-availability cluster with Pacemaker. It even makes common configuration mistakes so that it can demonstrate how to fix them.
On the other hand, if you're looking for an exhaustive reference of all of Pacemaker's options and features, try Pacemaker Explained. It's dry, but should have the answers you're looking for.
- There is also a project wiki + There is also a project wiki with examples, how-to guides, and other information that doesn't make it into the manuals.
| man(1) pages | [html] |
| Ordering Explained | -[pdf] | -
| Colocation Explained | -[pdf] | -
| Configuring Fencing with crmsh | [html] |
$desc
\n"; } $build = file_get_contents("$base/build-$version.txt"); if (!empty($build)) { echo "$build
\n"; } } function sphinx_docs_for_version($base, $version) { echo "| " . str_replace("_", " ", $book) . " | \n"; echo ""; foreach ($formats as $format) { $format_name = basename($format); if (strncmp($format_name, "build-", 6) !== 0) { if ($format_name == "pdf") { $link = "$format/$book.pdf"; } else { $link = "$format/"; } echo " [" . $format_name . "]"; } } echo " | \n"; echo "
| '.str_replace("_", " ", $b)." ($lang) | "; echo ''; foreach (glob("$base/$lang/Pacemaker/$version/epub/$b/*.epub") as $filename) { echo " [epub]"; } foreach (glob("$base/$lang/Pacemaker/$version/pdf/$b/*.pdf") as $filename) { echo " [pdf]"; } foreach (glob("$base/$lang/Pacemaker/$version/html/$b/index.html") as $filename) { echo " [html]"; } foreach (glob("$base/$lang/Pacemaker/$version/html-single/$b/index.html") as $filename) { echo " [html-single]"; } foreach (glob("$base/$lang/Pacemaker/$version/txt/$b/*.txt") as $filename) { echo " [txt]"; } echo " |
+ "The definitive open-source high-availability stack for the Linux + platform builds upon the Pacemaker cluster resource manager." + -- LINUX Journal, + "Ahead + of the Pack: the Pacemaker High-Availability Stack" +-
- "The definitive open-source high-availability stack for the Linux - platform builds upon the Pacemaker cluster resource manager." - -- LINUX Journal, - "Ahead - of the Pack: the Pacemaker High-Availability Stack" -- - -
-
- - Pacemaker has been around since - 2004 - and is a collaborative effort by the ClusterLabs community, including - full-time developers with - Red Hat - and SuSE. -
-- Pacemaker ships with most modern Linux distributions and has been - deployed in many critical environments including Deutsche - Flugsicherung GmbH - (DFS) - which uses Pacemaker to ensure - its air traffic - control systems are always available. -
-- Andrew Beekhof was - Pacemaker's original author and long-time project lead. The current - project lead is Ken Gaillot. -
-
+
+ + Pacemaker has been around since + 2004 + and is a collaborative effort by the ClusterLabs community, including + full-time developers with + Red Hat + and SuSE. +
++ Pacemaker ships with most modern Linux distributions and has been + deployed in many critical environments including Deutsche + Flugsicherung GmbH + (DFS) + which uses Pacemaker to ensure + its air traffic + control systems are always available. +
++ Andrew Beekhof was + Pacemaker's original author and long-time project lead. The current + project lead is Ken Gaillot. +
+
