The feature was announced by the following e-mail: -------- Forwarded Message -------- Subject: [ClusterLabs] Coming in Pacemaker 2.0.5: on-fail=demote / no-quorum-policy=demote Date: Mon, 10 Aug 2020 11:47:24 -0500 From: Ken Gaillot <[email protected]> Reply-To: Cluster Labs - All topics related to open-source clustering welcomed <[email protected]> Organization: Red Hat To: Cluster Labs - All topics related to open-source clustering welcomed <[email protected]>
Hi all, Looking ahead to the Pacemaker 2.0.5 release expected at the end of this year, here is a new feature already in the master branch. When configuring resource operations, Pacemaker lets you set an "on- fail" policy to specify whether to restart the resource, fence the node, etc., if the operation fails. With 2.0.5, a new possible value will be "demote", which will mean "demote this resource but do not fully restart it". "Demote" will be a valid value only for promote actions, and for recurring monitors with "role" set to "Master". Once the resource is demoted, it will be eligible for promotion again, so if the promotion scores have not changed, a promote on the same node may be attempted. If this is not desired, the agent can change the promotion scores either in the failed monitor or the demote. The intended use case is an application where a successful demote assures a well-functioning service, and a full restart would be unnecessarily heavyweight. A large database might be an example. Similarly, Pacemaker offers the cluster-wide "no-quorum-policy" option to specify what happens to resources when quorum is lost (the default being to stop them). With 2.0.5, "demote" will be a possible value here as well, and will mean "demote all promotable resources and stop all other resources". The intended use case is an application that cannot cause any harm after being demoted, and may be useful in a demoted role even if there is no quorum. A database that operates read-only when demoted and doesn't depend on any non-promotable resources might be an example. Happy clustering :) -- Ken Gaillot <[email protected]> ** Description changed: In bug: https://bugs.launchpad.net/ubuntu/+source/pacemaker/+bug/1895883 I did the stabilization patches for pacemaker 2.0.4.. and I did not merge this feature so it could have its own FFe (this bug). The following patch-set: * #### this is the no-quorum-policy feature microsoft needs for mssqlserver |\ | * c4429d86e - Log: scheduler: downgrade "active on" messages to trace (3 mont | * 7eec572db - Build: libcrmcommon: bump CRM feature set (3 months ago) <Ken G | * 01c5ec67e - Low: scheduler: match initial no-quorum-policy struct value to | * 015b5c012 - Doc: Pacemaker Explained: document no-quorum-policy=demote (3 m | * 5d809e136 - Test: scheduler: add regression test for no-quorum-policy="demo | * b1ae35938 - Feature: scheduler: support "demote" choice for no-quorum-polic | * 0b6834453 - Refactor: scheduler: functionize checking quorum policy in effe | * d4b9117e7 - Doc: Pacemaker Explained: correct on-fail default (3 months ago | * 204961e95 - Doc: Pacemaker Explained: document new on-fail="demote" option | * d29433ea5 - Test: scheduler: add regression tests for on-fail="demote" (3 m | * 874f75e0f - Feature: scheduler: new on-fail="demote" recovery policy for pr | * 2f1e2df1f - Feature: xml: add on-fail="demote" option to resources schema ( | * fd55a6660 - Doc: libpacemaker: improve comments for resource state and acti | * 98c3b649f - Log: libpacemaker: check for re-promotes specifically (3 months | * ff6aebecf - Doc: libpacemaker: improve comments when logging actions (3 mon | * f2d244bc4 - Test: scheduler: test forcing a restart instead of reload when | * a4d6a20a9 - Low: libpacemaker: don't force stop when skipping reload of fai | * 8dceba792 - Refactor: scheduler: use more appropriate types in a couple pla | * ef246ff05 - Fix: scheduler: disallow on-fail=stop for stop operations (3 mo | * f1f71b3f3 - Refactor: scheduler: functionize comparing on-fail values (3 mo * implements the : new on-fail="demote" recovery policy needed for Microsoft SQL Server big installations. MSSQL server does not use pacemaker for fencing, but it does need the promote/demote features available for it.. to coordinate its HA cluster. This request come directly by Microsoft after the feature was developed upstream. + I'm particularly interested in this feature because it allows Microsoft + SQL Server to use it. MSSQL server uses pacemaker to manage which node + is the primary node, but it does not need fencing mechanisms and this + feature allows it to simply promote/demote the nodes. Without it, big + clusters with MSSQL server installed might face big downtime because of + fencing and the database archive logs recovery. + Note: This will help me trying to backport the feature to Focal. ** Also affects: pacemaker (Ubuntu Focal) Importance: Undecided Status: New ** Changed in: pacemaker (Ubuntu Focal) Importance: Undecided => Wishlist ** Changed in: pacemaker (Ubuntu) Importance: Undecided => High -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1896223 Title: [FFe] this is the no-quorum-policy feature (specially for mssql sevrer) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/pacemaker/+bug/1896223/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
