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]> _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/
