Hi, I put a patch in to HEAD / RHEL4 / RHEL5 / STABLE branches that obviates the need to configure fence_manual for use in clusters, and allows manual override if fencing fails. Here's how it works: 1. Try fencing as usual 2. If fencing *fails*, open a manual override socket and wait for user input for a few seconds. 3. If we get no input, start the loop over... Why does it obviate manual fencing? * If you have no fencing configured, fencing immediately fails (this is part of the designed-in behavior of fenced!), thereby activating the possibility of using the manual override. I.e. No fencing implies "manual override only"! How is this better than manual fencing? * You do not have to configure fencing at all in order for this to work. (Woooo! Simpler configurations rock!) * This is a general manual override case which works with all types of fencing, without hanging forever waiting for input. * The fence devices, if configured, will be retried. Previously, if you used fence_manual as a backup, you *had* to use fence_ack_manual -- even if the problem with the fence device was only suffering a temporary problem (ex: a network fencing device that only allows one login at a time). * Since both methods require manual intervention, the net effect is approximately the same in the "no-fencing" case. In fact, I committed a sample "fence_ack_manual" shell script replacement which works like the original command (note: script is only in -HEAD branch). Why did I do this? * I think that you should not have to configure manual fencing in order for it to work; it should the default behavior. * I think this is a better and more general solution to a problem where a fence device fails. Currently, the only way to un-break a cluster where fencing is permanently dead is to do something like "mv /sbin/fence_foo /sbin/fence_foo.bak; cp /bin/true /sbin/fence_foo" - and reverse the process after fencing completes. Why did I bother to write this up? * I want to remove the fence_manual and fence_ack_manual commands (from the HEAD branch), and I want to replace fence_ack_manual with the shell script that does the same thing with the patch. If anyone has strong opinions against this, please comment. What other information is there? * fence*manual will not go away in the RHEL4/RHEL5 branches. * This should not impact your configuration -- even if you are a fence_manual consumer. If you are using RHEL4, STABLE, or RHEL5 branches, your configuration will still work. * Even if you are using HEAD, the removal of fence_manual from your system (but not your configuration) with this new feature will simply cause fencing to immediately fail, activating the manual override. Comments? Can I nuke fence_manual and fence_ack_manual from the HEAD trunk of CVS? :) -- Lon -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
