On 02/17/2017 08:43 AM, Ilia Sokolinski wrote: > Thank you! > > What quantity does pacemaker tries to equalize - number of running resources > per node or total stickiness per node? > > 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? > > Ilia
By default, pacemaker simply chooses the node with the fewest resources when placing a resource (subject to your constraints, of course). However you can have much more control if you want: http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-single/Pacemaker_Explained/index.html#idm139683960632560 > > > >> 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