>>> Andrei Borzenkov <arvidj...@gmail.com> schrieb am 21.03.2020 um 18:22 in Nachricht <14318_1584811393_5E764D80_14318_174_1_6ab730d7-8cf0-2c7d-7ae5-8d0ea8402758@gmai .com>: > 21.03.2020 20:07, Ken Gaillot пишет: >> Hi all, >> >> I am happy to announce a feature that was discussed on this list a >> while back. It will be in Pacemaker 2.0.4 (the first release candidate >> is expected in about three weeks). >> >> A longstanding concern in two-node clusters is that in a split brain, >> one side must get a fencing delay to avoid simultaneous fencing of both >> nodes, but there is no perfect way to determine which node gets the >> delay. >> >> The most common approach is to configure a static delay on one node. >> This is particularly useful in an active/passive setup where one >> particular node is normally assigned the active role. >> >> Another approach is to use the relatively new fence_heuristics_ping >> agent in a topology with your real fencing agent. A node that can ping >> a configured IP will be more likely to survive. >> >> In addition, we now have a new cluster-wide property, priority-fencing- >> delay, that bases the delay on what resources were known to be active >> where just before the split. If you set the new property, and configure >> priorities for your resources, the node with the highest combined >> priority of all resources running on it will be more likely to survive. >> >> As an example, if you set a default priority of 1 for all resources, >> and set priority-fencing-delay to 15s, then the node running the most >> resources will be more likely to survive because the other node will >> wait 15 seconds before initiating fencing. If a particular resource is >> more important than the rest, you can give it a higher priority. >> > > That sounds good except one consideration. "priority" also affects > resource placement, and changing it may have rather unexpected results, > especially in cases when scores are carefully selected to achieve > resource distribution.
I've always seen pririties as "super odering" constraints: Try to run the important resources first (what ever their dependencies or scores are). [...] Regards, Ulrich _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/