[ClusterLabs] Antw: Re: Pacemaker quorum behavior

[Ulrich Windl]

>>> "Scott Greenlese" <swgreenl at us.ibm.com> schrieb am 08.09.2016 um 16:20 in
Nachricht
<OF0AFDC7DC.21EC44D5-ON00258028.004E42A7-85258028.004EC93E at notes.na.collabserv.c 
m>:

> Correction...
> 
> When I stopped pacemaker/corosync on the four (powered on / active) cluster
> node hosts,  I was having an issue with
> the gentle method of stopping the cluster (pcs cluster stop --all), so I
> ended up doing individual (pcs cluster kill <cluster_node>)
> on each of the four cluster nodes.   I then had to stop the virtual domains
> manually via 'virsh destroy <guestname>' on each host.
> Perhaps there was some residual node status affecting my quorum?

I don't know Redhat, but in SuSE SLES I use "rcopenais stop" to shutdown one node cleanly. If resources are running this can take a few minutes to complete, especially if VMs have to be shut down or migrated to other nodes.
I suggest to inspect the logs to see what was going on.

> 
> Thanks...
> 
> Scott Greenlese ... IBM Solutions Test,  Poughkeepsie, N.Y.
>   INTERNET:  swgreenl at us.ibm.com 
>   PHONE:  8/293-7301 (845-433-7301)    M/S:  POK 42HA/P966
> 
> 
> 
> 
> From:	Scott Greenlese/Poughkeepsie/IBM at IBMUS
> To:	users at clusterlabs.org 
> Cc:	Si Bo Niu <niusibo at cn.ibm.com>, Scott
>             Loveland/Poughkeepsie/IBM at IBMUS, Michael
>             Tebolt/Poughkeepsie/IBM at IBMUS
> Date:	09/08/2016 10:01 AM
> Subject:	[ClusterLabs] Pacemaker quorum behavior
> 
> 
> 
> Hi all...
> 
> I have a few very basic questions for the group.
> 
> I have a 5 node (Linux on Z LPARs) pacemaker cluster with 100 VirtualDomain
> pacemaker-remote nodes
> plus 100 "opaque" VirtualDomain resources. The cluster is configured to be
> 'symmetric' and I have no
> location constraints on the 200 VirtualDomain resources (other than to
> prevent the opaque guests
> from running on the pacemaker remote node resources). My quorum is set as:
> 
> quorum {
> provider: corosync_votequorum
> }
> 
> As an experiment, I powered down one LPAR in the cluster, leaving 4 powered
> up with the pcsd service up on the 4 survivors
> but corosync/pacemaker down (pcs cluster stop --all) on the 4 survivors. I
> then started pacemaker/corosync on a single cluster
> node (pcs cluster start), and this resulted in the 200 VirtualDomain
> resources activating on the single node.
> This was not what I was expecting. I assumed that no resources would
> activate / start on any cluster nodes
> until 3 out of the 5 total cluster nodes had pacemaker/corosync running.
> 
> After starting pacemaker/corosync on the single host (zs95kjpcs1), this is
> what I see :
> 
> [root at zs95kj VD]# date;pcs status |less
> Wed Sep 7 15:51:17 EDT 2016
> Cluster name: test_cluster_2
> Last updated: Wed Sep 7 15:51:18 2016 Last change: Wed Sep 7 15:30:12 2016
> by hacluster via crmd on zs93kjpcs1
> Stack: corosync
> Current DC: zs95kjpcs1 (version 1.1.13-10.el7_2.ibm.1-44eb2dd) - partition
> with quorum
> 106 nodes and 304 resources configured
> 
> Node zs93KLpcs1: pending
> Node zs93kjpcs1: pending
> Node zs95KLpcs1: pending
> Online: [ zs95kjpcs1 ]
> OFFLINE: [ zs90kppcs1 ]
> 
> .
> .
> .
> PCSD Status:
> zs93kjpcs1: Online
> zs95kjpcs1: Online
> zs95KLpcs1: Online
> zs90kppcs1: Offline
> zs93KLpcs1: Online
> 
> So, what exactly constitutes an "Online" vs. "Offline" cluster node w.r.t.
> quorum calculation? Seems like in my case, it's "pending" on 3 nodes,
> so where does that fall? Any why "pending"? What does that mean?
> 
> Also, what exactly is the cluster's expected reaction to quorum loss?
> Cluster resources will be stopped or something else?
> 
> Where can I find this documentation?
> 
> Thanks!
> 
> Scott Greenlese - IBM Solution Test Team.
> 
> 
> 
> Scott Greenlese ... IBM Solutions Test, Poughkeepsie, N.Y.
> INTERNET: swgreenl at us.ibm.com 
> PHONE: 8/293-7301 (845-433-7301) M/S: POK 42HA/P966
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