On 11/30/2012 05:04 PM, Hermes Flying wrote: > Hi, > I am looking into using your facilities to have high availability on my > system. I am trying to figure out some things. I hope you guys could help me. > I am interested in knowing how pacemaker migrates a VIP and how a splitbrain > situation is address by your facilities. > To be specific: I am interested in the following setup: > > 2 linux machines. Each machine runs a load balancer and a Tomcat instance. > If I understand correctly pacemaker will be responsible to assign the main > VIP to one of the nodes.
Pacemaker can handle virtual IP addresses, but it's more of a fail-over system, rather than a load-balancing, round-robin system. For load balancing, look at Red Hat's "LVS". > My questions are: > 1)Will pacemaker monitor/restart the load balancers on each machine in case > of crash? It can monitor/recover/relocate any service that uses init.d style scripts. If a script/service responds properly to stop, status and start, you're good to go. > 2) How does pacemaker decide to migrate the VIP to the other node? At the most simple; When the machine hosting the VIP fails, it will relocate. You can control how, when and where the VIP fails back (look at 'resource stickiness'). > 3) Do the pacemakers in each machine communicate? If yes how do you handle > network failure? Could I end up with split-brain? Pacemaker uses corosync for cluster membership, quorum and fencing. A properly configured fence device (aka "stonith"), will prevent a split brain. If you disable or fail to properly setup fencing, split brains are possible and even likely. > 4) Generally how is split-brain addressed using pacemaker? Fencing to prevent it. > 5) Could pacemaker monitor Tomcat? If it supports stop, start and status, yes. > As you can see I am interested in maintain quorum in a two-node > configuration. If you can help me with this info to find a proper direction > it would be much appreciated! Quorum needs to be disabled in a two-node cluster. This is fine with good fencing. To learn more, please see the documentation available here: http://clusterlabs.org/doc/ -- 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
