ClusterStack

Revision 1 as of 2009-06-13 18:08:57

Launchpad Entry: server-karmic-cluster-stack
Created: 13 Jun 2009
Contributors: AnteKaramatic
Packages affected:

Summary

This specification focuses on fully integrated cluster stack. It defines which tools are going to be used to define high availability and load balancing cluster system.

Release Note

Rationale

Up till now, default cluster system in Ubuntu was Red Hat Cluster System. Even though it's a good platform, not many system administrators use it in Ubuntu. Most of the administrators rather use heartbeat. Problem with heartbeat is that it isn't being developed any more. At least not in the form it was until now.

There's an intention to bring all Linux clustering options more closer to each other. Pacemaker was chosen as a base for this project. So, Ubuntu needs to keep track with upstream and define it's cluster stack according to decisions made at the Cluster Summit in Prague, 2008.

Use cases

Rick wants fail over cluster for his MySQL service. He installs predefined cluster stack and configures MySQL service.
Matt already has Red Hat Cluster Suite setup in Ubuntu 9.04 and he wants to migrate to Ubuntu 9.10 and this new cluster stack we offer.

Design

Components of mail stack

pacemaker
openais-legacy
openais
corosync
redhat-cluster-suite
drbd

Pacemaker

Pacemaker is core of new cluster stack. It's job is to start, stop and monitor resources which cluster provides. It can use openais-legacy or heartbeat (2.99.x|3.x) as a messaging and membership layer. It also contains parts of old heartbeat code.

For Karmic and further releases, openais-legacy will be default messaging and membership layer, until pacemaker moves to newer openais (under development) version. Pacemaker with heartbeat as a messaging layer will also be provided, but it will not be supported, since development of heartbeat is discontinued. 3.x release should be the last, but it will work only as a messaging layer for pacemaker - it will not be able to provide full cluster suite anymore.

OpenAIS-legacy

OpenAIS-legacy is name for current stable version of openais - whitetank. Pacemaker and probably Red Hat Cluster Suite will be buit on top of these version of openais, until openais/corosync get to version 1.0.

OpenAIS

OpenAIS-legacy was split into two trees - openais and corosync. These are still development versions, without a stable API. Once they get stable, Pacemaker will be built with support for them. This should happen before Karmic release or at least Karmic+1.

Corosync

Corosync Cluster Engine allows any third party to implement plugin cluster services using the infrastructure provided. It's needed for new OpenAIS.

Red Hat Cluster Suite

Until now, Red Hat Cluster Suite was the supported cluster stack in Ubuntu. It's also based on openais-legacy or openais/corosync. We should provide migration documentation or tools for those that want to move from Red Hat Cluster Suite to Pacemaker/OpenAIS.

DRBD

DRBD is block device that enables network RAID1 mirrors. Default cluster stack in Ubuntu should provide tools for managing clusters with DRBD devices.

Implementation

Restrictions

Test/Demo Plan

Testing packages will be provided in Ubuntu-HA PPA. Packages should be built in cooperation with Debian HA team.

Plan is to provide stable pacemaker-openais packages and to work on redhat-cluster-suite in parallel. Goal is to have pacemaker-openais in main and both pacemaker-heartbeat and redhat-cluster-suite in universe. We should also drop old heartbeat infrastructure, since it's unmaintained and obsoleted by these tools.

Unresolved Issues

BoF agenda and discussion

Karmic UDS notes

These are the notes from UDS session:
= Ubuntu Cluster Stack =

Discussed options:
 * Redhat Cluster Suite
 * Heartbeat
  * Going to die.
 * Pacemaker
  * http://clusterlabs.org/wiki/Main_Page

Upstream status:
 * Movement to standardize on cluster between distros.

Plans:
 * ubuntu-ha team to approach Debian team for a joint work on cluster stack
 * Create templates for cluster stack to make it easier to deploy
 * Management tool for setting up, and maintaining clusters

Goal for Karmic:
  * Focus on Pacemaker/OpenAIS setup as a future cluster stack and keep Redhat Cluster Suite until Pacemaker is ready.
  * Update RHCS to latest version and make it easier to setup
  * Documentation for RHCS/Pacemaker with DRBD.
   * HA Cluster
   * Add to Server Guide
 * OpenAIS
  * Will need a guide for migrating from RHCS to Pacemaker/OpenAIS.
 * Everything is in the archive, just needs some polish.

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