Hi, I have taken a look at the documentation about booth. The problem is that it need a third independent arbitrator on a third connection that I don't have, which will grant or remove ticket.
My idea about fencing is to send an ssh command to reboot the server or just corosync but only from one server. When there is a network problem : With my constraint on ping I can assume that only one server will be running openvpn. When network is back node1 will restart node2 to avoid problem. Do you think that could work ? I know it's dirty but I don't have another idea. And how can I configure this sort of fencing on only one server ? Thanks -----Message d'origine----- De : [email protected] [mailto:[email protected]] De la part de Digimer Envoyé : jeudi 27 février 2014 19:07 À : General Linux-HA mailing list Objet : Re: [Linux-HA] 2 Nodes split brain, distant sites For fencing to work, it must actually cut off the other node. Simply returning a fake success will cause a split-brain. On 27/02/14 12:38 PM, TRIBOLET Thomas wrote: > Hi, > > Thanks for your response. > > I'll try booth plugin. It's in debian repository. > > If it don't work I'll try making a fake fencing agent that will only > restart corosync. ( It seems it fix the problem ) > > > Thanks > ________________________________________ > De : [email protected] > [[email protected]] de la part de Digimer > [[email protected]] Envoyé : jeudi 27 février 2014 17:05 À : General > Linux-HA mailing list Objet : Re: [Linux-HA] 2 Nodes split brain, > distant sites > > On 27/02/14 09:42 AM, TRIBOLET Thomas wrote: >> 2) My problem : >> >> When there is a network problem : >> >> Ex : >> a) first-node site lost internet connection ( and communication with >> second-node at same time due to vpn on internet connection ) >> b) cluster stop openvpn on first node and launch it on second due to >> primitive p_ping in config. >> c) connection come back on first-node site >> d) Problem : first-node and second-node don't bring back cluster, the don't >> see each other and create a cluster on each node -> split brain I think. >> e) Each node has openvpn running which shouldn't happen >> >> >> I don't have stonith running because I think without quorum it will >> be problematic Is there a way to say to corosync to recreate a ring ? >> >> Or have someone another solution ? >> >> Thanks > > Bonjour, > > This is the fundamental problem of "stretch" clusters (or > geo-clusters). There is no way to tell the difference between a site > failure and a network failure. In either case, the link is down, so > fencing can't be used. Without fencing, there is no way to avoid a > split-brain. > > As for quorum; When quorum isn't used, fencing becomes *more* > important. Even then, quorum and fencing solve different problems. > Quorum is useful when nodes are acting in a defined manner. Fencing is > needed when a node is in an unknown state (and thus acting in an > undefined manner). > > So regardless of quorum, fencing is required. It is the only way > to reliably avoid split-brains. Unfortunately, fencing doesn't work on > stretch clusters. > > The pacemaker project is working on something called "booth" which > is designed to deal with this problem, but I don't know much about it, > or whether it's out of testing/dev yet. > > So in short, if you must have a stretch cluster, I recommend > manual failover only. > > -- > Digimer > Papers and Projects: https://alteeve.ca/w/ What if the cure for cancer > is trapped in the mind of a person without access to education? > _______________________________________________ > Linux-HA mailing list > [email protected] > http://lists.linux-ha.org/mailman/listinfo/linux-ha > See also: http://linux-ha.org/ReportingProblems > _______________________________________________ > Linux-HA mailing list > [email protected] > http://lists.linux-ha.org/mailman/listinfo/linux-ha > See also: http://linux-ha.org/ReportingProblems > -- Digimer Papers and Projects: https://alteeve.ca/w/ What if the cure for cancer is trapped in the mind of a person without access to education? _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
