[ClusterLabs] Running several instances of a Corosync/Pacemaker cluster on a node
Is it possible to run several instances of a Corosync/Pacemaker clusters on a node? Can a node be a member of several clusters, so they could put resources there? I'm sure it's doable with separate nodes or containers, but that's not the case. My case is to separate data-critical resources, like storage or VIPs, from the complex resources like DB or MQ clusters. The latter should run with no-quorum-policy=ignore as they know how to deal with network partitions/split-brain, use own techniques to protect data and don't want external fencing from a Pacemaker, which no-quorum-policy/STONITH is. The former must use STONITH (or a stop policy, if it's only a VIP), as they don't know how to deal with split-brain, for example. -- Best regards, Bogdan Dobrelya, Irc #bogdando ___ 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
Re: [ClusterLabs] Running several instances of a Corosync/Pacemaker cluster on a node
On 26.04.2016 10:33, Bogdan Dobrelya wrote: > Is it possible to run several instances of a Corosync/Pacemaker clusters > on a node? Can a node be a member of several clusters, so they could put > resources there? I'm sure it's doable with separate nodes or containers, > but that's not the case. > > My case is to separate data-critical resources, like storage or VIPs, > from the complex resources like DB or MQ clusters. > > The latter should run with no-quorum-policy=ignore as they know how to > deal with network partitions/split-brain, use own techniques to protect > data and don't want external fencing from a Pacemaker, which > no-quorum-policy/STONITH is. > > The former must use STONITH (or a stop policy, if it's only a VIP), as > they don't know how to deal with split-brain, for example. And how would you cope with one of the storage nodes STONITHing one of the DB nodes? Regards, Robert ___ 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
Re: [ClusterLabs] Running several instances of a Corosync/Pacemaker cluster on a node
Am Dienstag, 26. April 2016, 10:33:00 schrieb Bogdan Dobrelya: > Is it possible to run several instances of a Corosync/Pacemaker clusters > on a node? Can a node be a member of several clusters, so they could put > resources there? I'm sure it's doable with separate nodes or containers, > but that's not the case. > > My case is to separate data-critical resources, like storage or VIPs, > from the complex resources like DB or MQ clusters. > > The latter should run with no-quorum-policy=ignore as they know how to > deal with network partitions/split-brain, use own techniques to protect > data and don't want external fencing from a Pacemaker, which > no-quorum-policy/STONITH is. > > The former must use STONITH (or a stop policy, if it's only a VIP), as > they don't know how to deal with split-brain, for example. that is not possible. corosync and pacemaker are not able to run as multi- tennen. Use docker or plain linux partitions (lxc). Mit freundlichen Grüßen, Michael Schwartzkopff -- [*] sys4 AG http://sys4.de, +49 (89) 30 90 46 64, +49 (162) 165 0044 Franziskanerstraße 15, 81669 München Sitz der Gesellschaft: München, Amtsgericht München: HRB 199263 Vorstand: Patrick Ben Koetter, Marc Schiffbauer Aufsichtsratsvorsitzender: Florian Kirstein signature.asc Description: This is a digitally signed message part. ___ 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
Re: [ClusterLabs] Running several instances of a Corosync/Pacemaker cluster on a node
On 04/26/2016 10:49 AM, Robert Dahlem wrote: > On 26.04.2016 10:33, Bogdan Dobrelya wrote: > >> Is it possible to run several instances of a Corosync/Pacemaker clusters >> on a node? Can a node be a member of several clusters, so they could put >> resources there? I'm sure it's doable with separate nodes or containers, >> but that's not the case. >> >> My case is to separate data-critical resources, like storage or VIPs, >> from the complex resources like DB or MQ clusters. >> >> The latter should run with no-quorum-policy=ignore as they know how to >> deal with network partitions/split-brain, use own techniques to protect >> data and don't want external fencing from a Pacemaker, which >> no-quorum-policy/STONITH is. >> >> The former must use STONITH (or a stop policy, if it's only a VIP), as >> they don't know how to deal with split-brain, for example. > > And how would you cope with one of the storage nodes STONITHing one of > the DB nodes? For that case, one should use separate clusters and sets of nodes. My case is like a VIP and a DB resources only. When the VIP has to be stopped in a minority partition, there is no need for STONITH but the no-quorum-policy=stop. While the DB resource should not be affected and keep running at the same node, either in a separate cluster - if that were possible - or in the same cluster - if quorum policy allowed to "exclude" resources from the stop lists. Too bad none of two is an option. > > Regards, > Robert > > ___ > 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 > -- Best regards, Bogdan Dobrelya, Irc #bogdando ___ 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
Re: [ClusterLabs] Running several instances of a Corosync/Pacemaker cluster on a node
On 04/26/2016 03:33 AM, Bogdan Dobrelya wrote: > Is it possible to run several instances of a Corosync/Pacemaker clusters > on a node? Can a node be a member of several clusters, so they could put > resources there? I'm sure it's doable with separate nodes or containers, > but that's not the case. > > My case is to separate data-critical resources, like storage or VIPs, > from the complex resources like DB or MQ clusters. > > The latter should run with no-quorum-policy=ignore as they know how to > deal with network partitions/split-brain, use own techniques to protect > data and don't want external fencing from a Pacemaker, which > no-quorum-policy/STONITH is. > > The former must use STONITH (or a stop policy, if it's only a VIP), as > they don't know how to deal with split-brain, for example. I don't think it's possible, though I could be wrong, if separate IPs/ports, chroots and node names are used (just shy of a container ...). However I suspect it would not meet your goal in any case. DB and MQ software generally do NOT have sufficient techniques to deal with a split-brain situation -- either you lose high availability or you corrupt data. Using no-quorum-policy=stop is fine for handling network splits, but it does not help if a node becomes unresponsive. Also note that pacemaker does provide the ability to treat different resources differently with respect to quorum and fencing, without needing to run separate clusters. See the "required" meta-attribute: http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-single/Pacemaker_Explained/index.html#_resource_meta_attributes I suspect your motive for this is to be able to run a cluster without fencing. There are certain failure scenarios that simply are not recoverable without fencing, regardless of what the application software can do. There is really only one case in which doing without fencing is reasonable: when you're willing to lose your data and/or have downtime when a situation arises that requires fencing. ___ 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
