Ilia Sokolinski <i...@clearskydata.com> writes: > Thank you! > > What quantity does pacemaker tries to equalize - number of running resources > per node or total stickiness per node? >
I honestly don't know exactly what the criteria are. Without any utilization definitions for nodes, I *think* it tries to balance the number of resources per node. But if the resources and nodes have cpu/memory utilization defined, the rules change. But I'm afraid I haven't dug into exactly what the logic looks like. > Suppose I have a bunch of web server groups each with IPaddr and apache > resources, and a fewer number of database groups each with IPaddr, postgres > and LVM resources. > > In that case, does it mean that 3 web server groups are weighted the same as > 2 database groups in terms of distribution? Good question, I think it looks purely at the primitive resources. Groups are just shorthand for a series of ordering and placement constraints. Cheers, Kristoffer > > Ilia > > > >> On Feb 17, 2017, at 2:58 AM, Kristoffer Grönlund <deceive...@gmail.com> >> wrote: >> >> Ilia Sokolinski <i...@clearskydata.com> writes: >> >>> Suppose I have a N node cluster where N > 2 running m*N resources. >>> Resources don’t have preferred nodes, but since resources take RAM and CPU >>> it is important to distribute them equally among the nodes. >>> Will pacemaker do the equal distribution, e.g. m resources per node? >>> If a node fails, will pacemaker redistribute the resources equally too, >>> e.g. m * N/(N-1) per node? >>> >>> I don’t see any settings controlling this behavior in the documentation, >>> but perhaps, pacemaker tries to be “fair” by default. >>> >> >> Yes, pacemaker tries to allocate resources evenly by default, and will >> move resources when nodes fail in order to maintain that. >> >> There are several different mechanisms that influence this behaviour: >> >> * Any placement constraints in general influence where resources are >> allocated. >> >> * You can set resource-stickiness to a non-zero value which determines >> to which degree Pacemaker prefers to leave resources running where >> they are. The score is in relation to other placement scores, like >> constraint scores etc. This can be set for individual resources or >> globally. [1] >> >> * If you have an asymmetrical cluster, resources have to be manually >> allocated to nodes via constraints, see [2] >> >> [1]: >> http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-single/Pacemaker_Explained/index.html#s-resource-options >> [2]: >> http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-single/Pacemaker_Explained/index.html#_asymmetrical_opt_in_clusters >> >> Cheers, >> Kristoffer >> >>> Thanks >>> >>> Ilia Sokolinski >>> _______________________________________________ >>> Users mailing list: Users@clusterlabs.org >>> http://lists.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 >> >> -- >> // Kristoffer Grönlund >> // kgronl...@suse.com > > > _______________________________________________ > Users mailing list: Users@clusterlabs.org > http://lists.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 -- // Kristoffer Grönlund // kgronl...@suse.com _______________________________________________ Users mailing list: Users@clusterlabs.org http://lists.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