Pacemaker supports fencing "topologies", allowing multiple fencing devices to be used (in conjunction or as fallbacks) when a node needs to be fenced.
However, there is a catch when using something like redundant power supplies. If you put two power switches in the same topology level, and Pacemaker needs to reboot the node, it will reboot the first power switch and then the second -- which has no effect since the supplies are redundant. Pacemaker's upstream master branch has new handling that will be part of the eventual 1.1.14 release. In such a case, it will turn all the devices off, then turn them all back on again. With previous versions, there was a complicated configuration workaround involving creating separate devices for the off and on actions. With the new version, it happens automatically, and no special configuration is needed. Here's an example where node1 is the affected node, and apc1 and apc2 are the fence devices: pcs stonith level add 1 node1 apc1,apc2 Of course you can configure it using crm or XML as well. The fencing operation will be treated as successful as long as the "off" commands succeed, because then it is safe for the cluster to recover any resources that were on the node. Timeouts and errors in the "on" phase will be logged but ignored. Any action-specific timeout for the remapped action will be used (for example, pcmk_off_timeout will be used when executing the "off" command, not pcmk_reboot_timeout). The new code knows to skip the "on" step if the fence agent has automatic unfencing (because it will happen when the node rejoins the cluster). This allows fence_scsi to work with this feature. -- Ken Gaillot <kgail...@redhat.com> _______________________________________________ Users mailing list: Users@clusterlabs.org http://clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org