[Pacemaker] Quorum in pacemaker

[emmanuel segura]

{I'm trying to set up a three node cluster using pacemaker+corosync} =
but you trying to use cman, depending on your distro you can use
different cluster es: cman + pacemaker or corosync+pacemaker

2014-06-27 2:22 GMT+02:00 Vijay B <os.vbvs at gmail.com>:
> Hi,
>
> I'm trying to set up a three node cluster using pacemaker+corosync, and I
> installed the required packages on each node, checked for their network
> connectivity so they can see each other, added the required startup scripts
> and edited the cluster.conf file as well so it includes all three nodes.
>
> Now, when on the first node, I attempt to start up cman using service cman
> start, it times out thus:
>
> vagrant at precise64-pmk1:~$ sudo service cman start
>
> Starting cluster:
>
>    Checking if cluster has been disabled at boot... [  OK  ]
>
>    Checking Network Manager... [  OK  ]
>
>    Global setup... [  OK  ]
>
>    Loading kernel modules... [  OK  ]
>
>    Mounting configfs... [  OK  ]
>
>    Starting cman... [  OK  ]
>
>    Waiting for quorum... Timed-out waiting for cluster
>
> [FAILED]
>
> vagrant at precise64-pmk1:~$
>
>
> Why is this? Is it because I have three nodes to begin with in my
> /etc/cluster/cluster.conf, and so this node expects that the cluster quorum
> is 2, and so it should be able to talk to at least one other node? At this
> point, I haven't started the cman or pacemaker services on the other nodes.
>
> If this is the case, what will happen when two nodes of the three die? In
> case cluster.conf changes accordingly to reflect the new cluster membership,
> what if all three nodes are simply powered off and one rebooted? The cluster
> will be down, won't it?
>
> What is the best way to get around this? I don't want to set
> CMAN_QUORUM_TIMEOUT=0, since as I understand it, the node would then go
> ahead and start itself as a cluster without waiting for the other nodes, and
> if this causes my service to start up and it is already started/running on
> another node, it could cause issues.
>
> Now, I don't know how to configure quorum disks for pacemaker - is it
> possible to do this with pacemaker? How does it work? What are the
> recommended ways to address the above problem? I infer that if this disk is
> configured, the node that grabs the disk first becomes the president of the
> pacemaker cluster. In this context, I have another question - does corosync
> have its own cluster membership state distributed across all cluster nodes?
> If so, I guess quorum is configured at the corosync level rather than at the
> pacemaker level?
>
> Apologies in advance if my queries above are addressed in the documentation
> already - I felt it would be quicker and more accurate to ask the community
> for reliable info.
>
> Thanks!
> Regards,
> Vijay
>
>
>
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