[ClusterLabs] Antw: Re: Antw: Unexpected Resource movement after failover
Ken Gaillot
kgaillot at redhat.com
Mon Oct 17 14:06:28 EDT 2016
On 10/17/2016 09:55 AM, Nikhil Utane wrote:
> I see these prints.
>
> pengine: info: rsc_merge_weights:cu_4: Rolling back scores from cu_3
> pengine: debug: native_assign_node:Assigning Redun_CU4_Wb30 to cu_4
> pengine: info: rsc_merge_weights:cu_3: Rolling back scores from cu_2
> pengine: debug: native_assign_node:Assigning Redund_CU5_WB30 to cu_3
>
> Looks like rolling back the scores is causing the new decision to
> relocate the resources.
> Am I using the scores incorrectly?
No, I think this is expected.
Your anti-colocation constraints place cu_2 and cu_3 relative to cu_4,
so that means the cluster will place cu_4 first if possible, before
deciding where the others should go. Similarly, cu_2 has a constraint
relative to cu_3, so cu_3 gets placed next, and cu_2 is the one left out.
The anti-colocation scores of -INFINITY outweigh the stickiness of 100.
I'm not sure whether setting stickiness to INFINITY would change
anything; hopefully, it would stop cu_3 from moving, but cu_2 would
still be stopped.
I don't see a good way around this. The cluster has to place some
resource first, in order to know not to place some other resource on the
same node. I don't think there's a way to make them "equal", because
then none of them could be placed to begin with -- unless you went with
utilization attributes, as someone else suggested, with
placement-strategy=balanced:
http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-single/Pacemaker_Explained/index.html#idm140521708557280
>
> [root at Redund_CU5_WB30 root]# pcs constraint
> Location Constraints:
> Resource: cu_2
> Enabled on: Redun_CU4_Wb30 (score:0)
> Enabled on: Redund_CU5_WB30 (score:0)
> Enabled on: Redund_CU3_WB30 (score:0)
> Enabled on: Redund_CU1_WB30 (score:0)
> Resource: cu_3
> Enabled on: Redun_CU4_Wb30 (score:0)
> Enabled on: Redund_CU5_WB30 (score:0)
> Enabled on: Redund_CU3_WB30 (score:0)
> Enabled on: Redund_CU1_WB30 (score:0)
> Resource: cu_4
> Enabled on: Redun_CU4_Wb30 (score:0)
> Enabled on: Redund_CU5_WB30 (score:0)
> Enabled on: Redund_CU3_WB30 (score:0)
> Enabled on: Redund_CU1_WB30 (score:0)
> Ordering Constraints:
> Colocation Constraints:
> cu_2 with cu_4 (score:-INFINITY)
> cu_3 with cu_4 (score:-INFINITY)
> cu_2 with cu_3 (score:-INFINITY)
>
>
> On Mon, Oct 17, 2016 at 8:16 PM, Nikhil Utane
> <nikhil.subscribed at gmail.com <mailto:nikhil.subscribed at gmail.com>> wrote:
>
> This is driving me insane.
>
> This is how the resources were started. Redund_CU1_WB30 was the DC
> which I rebooted.
> cu_4(ocf::redundancy:RedundancyRA):Started Redund_CU1_WB30
> cu_2(ocf::redundancy:RedundancyRA):Started Redund_CU5_WB30
> cu_3(ocf::redundancy:RedundancyRA):Started Redun_CU4_Wb30
>
> Since the standby node was not UP. I was expecting resource cu_4 to
> be waiting to be scheduled.
> But then it re-arranged everything as below.
> cu_4(ocf::redundancy:RedundancyRA):Started Redun_CU4_Wb30
> cu_2(ocf::redundancy:RedundancyRA):Stopped
> cu_3(ocf::redundancy:RedundancyRA):Started Redund_CU5_WB30
>
> There is not much information available in the logs on new DC. It
> just shows what it has decided to do but nothing to suggest why it
> did it that way.
>
> notice: Start cu_4(Redun_CU4_Wb30)
> notice: Stop cu_2(Redund_CU5_WB30)
> notice: Move cu_3(Started Redun_CU4_Wb30 -> Redund_CU5_WB30)
>
> I have default stickiness set to 100 which is higher than any score
> that I have configured.
> I have migration_threshold set to 1. Should I bump that up instead?
>
> -Thanks
> Nikhil
>
> On Sat, Oct 15, 2016 at 12:36 AM, Ken Gaillot <kgaillot at redhat.com
> <mailto:kgaillot at redhat.com>> wrote:
>
> On 10/14/2016 06:56 AM, Nikhil Utane wrote:
> > Hi,
> >
> > Thank you for the responses so far.
> > I added reverse colocation as well. However seeing some other issue in
> > resource movement that I am analyzing.
> >
> > Thinking further on this, why doesn't "/a not with b" does not
> imply "b
> > not with a"?/
> > Coz wouldn't putting "b with a" violate "a not with b"?
> >
> > Can someone confirm that colocation is required to be configured both ways?
>
> The anti-colocation should only be defined one-way. Otherwise,
> you get a
> dependency loop (as seen in logs you showed elsewhere).
>
> The one-way constraint is enough to keep the resources apart.
> However,
> the question is whether the cluster might move resources around
> unnecessarily.
>
> For example, "A not with B" means that the cluster will place B
> first,
> then place A somewhere else. So, if B's node fails, can the cluster
> decide that A's node is now the best place for B, and move A to
> a free
> node, rather than simply start B on the free node?
>
> The cluster does take dependencies into account when placing a
> resource,
> so I would hope that wouldn't happen. But I'm not sure. Having some
> stickiness might help, so that A has some preference against moving.
>
> > -Thanks
> > Nikhil
> >
> > /
> > /
> >
> > On Fri, Oct 14, 2016 at 1:09 PM, Vladislav Bogdanov
> > <bubble at hoster-ok.com <mailto:bubble at hoster-ok.com>
> <mailto:bubble at hoster-ok.com <mailto:bubble at hoster-ok.com>>> wrote:
> >
> > On October 14, 2016 10:13:17 AM GMT+03:00, Ulrich Windl
> > <Ulrich.Windl at rz.uni-regensburg.de
> <mailto:Ulrich.Windl at rz.uni-regensburg.de>
> > <mailto:Ulrich.Windl at rz.uni-regensburg.de
> <mailto:Ulrich.Windl at rz.uni-regensburg.de>>> wrote:
> > >>>> Nikhil Utane <nikhil.subscribed at gmail.com <mailto:nikhil.subscribed at gmail.com>
> > <mailto:nikhil.subscribed at gmail.com
> <mailto:nikhil.subscribed at gmail.com>>> schrieb am 13.10.2016 um
> > >16:43 in
> > >Nachricht
> > ><CAGNWmJUbPucnBGXroHkHSbQ0LXovwsLFPkUPg1R8gJqRFqM9Dg at mail.gmail.com
> <mailto:CAGNWmJUbPucnBGXroHkHSbQ0LXovwsLFPkUPg1R8gJqRFqM9Dg at mail.gmail.com>
> >
> <mailto:CAGNWmJUbPucnBGXroHkHSbQ0LXovwsLFPkUPg1R8gJqRFqM9Dg at mail.gmail.com
> <mailto:CAGNWmJUbPucnBGXroHkHSbQ0LXovwsLFPkUPg1R8gJqRFqM9Dg at mail.gmail.com>>>:
> > >> Ulrich,
> > >>
> > >> I have 4 resources only (not 5, nodes are 5). So then I only need 6
> > >> constraints, right?
> > >>
> > >> [,1] [,2] [,3] [,4] [,5] [,6]
> > >> [1,] "A" "A" "A" "B" "B" "C"
> > >> [2,] "B" "C" "D" "C" "D" "D"
> > >
> > >Sorry for my confusion. As Andrei Borzenkovsaid in
> > ><CAA91j0W+epAHFLg9u6VX_X8LgFkf9Rp55g3nocY4oZNA9BbZ+g at mail.gmail.com
> <mailto:CAA91j0W%2BepAHFLg9u6VX_X8LgFkf9Rp55g3nocY4oZNA9BbZ%2Bg at mail.gmail.com>
> >
> <mailto:CAA91j0W%2BepAHFLg9u6VX_X8LgFkf9Rp55g3nocY4oZNA9BbZ%2Bg at mail.gmail.com
> <mailto:CAA91j0W%252BepAHFLg9u6VX_X8LgFkf9Rp55g3nocY4oZNA9BbZ%252Bg at mail.gmail.com>>>
> > >you probably have to add (A, B) _and_ (B, A)! Thinking about it, I
> > >wonder whether an easier solution would be using "utilization": If
> > >every node has one token to give, and every resource needs on token, no
> > >two resources will run on one node. Sounds like an easier solution to
> > >me.
> > >
> > >Regards,
> > >Ulrich
> > >
> > >
> > >>
> > >> I understand that if I configure constraint of R1 with R2 score as
> > >> -infinity, then the same applies for R2 with R1 score as -infinity
> > >(don't
> > >> have to configure it explicitly).
> > >> I am not having a problem of multiple resources getting schedule on
> > >the
> > >> same node. Rather, one working resource is unnecessarily getting
> > >relocated.
> > >>
> > >> -Thanks
> > >> Nikhil
> > >>
> > >>
> > >> On Thu, Oct 13, 2016 at 7:45 PM, Ulrich Windl <
> > >> Ulrich.Windl at rz.uni-regensburg.de
> <mailto:Ulrich.Windl at rz.uni-regensburg.de>
> > <mailto:Ulrich.Windl at rz.uni-regensburg.de
> <mailto:Ulrich.Windl at rz.uni-regensburg.de>>> wrote:
> > >>
> > >>> Hi!
> > >>>
> > >>> Don't you need 10 constraints, excluding every possible pair of your
> > >5
> > >>> resources (named A-E here), like in this table (produced with R):
> > >>>
> > >>> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
> > >>> [1,] "A" "A" "A" "A" "B" "B" "B" "C" "C" "D"
> > >>> [2,] "B" "C" "D" "E" "C" "D" "E" "D" "E" "E"
> > >>>
> > >>> Ulrich
> > >>>
> > >>> >>> Nikhil Utane <nikhil.subscribed at gmail.com <mailto:nikhil.subscribed at gmail.com>
> > <mailto:nikhil.subscribed at gmail.com
> <mailto:nikhil.subscribed at gmail.com>>> schrieb am 13.10.2016
> > >um
> > >>> 15:59 in
> > >>> Nachricht
> > >>>
> > ><CAGNWmJW0CWMr3bvR3L9xZCAcJUzyczQbZEzUzpaJxi+Pn7Oj_A at mail.gmail.com
> <mailto:CAGNWmJW0CWMr3bvR3L9xZCAcJUzyczQbZEzUzpaJxi%2BPn7Oj_A at mail.gmail.com>
> >
> <mailto:CAGNWmJW0CWMr3bvR3L9xZCAcJUzyczQbZEzUzpaJxi%2BPn7Oj_A at mail.gmail.com
> <mailto:CAGNWmJW0CWMr3bvR3L9xZCAcJUzyczQbZEzUzpaJxi%252BPn7Oj_A at mail.gmail.com>>>:
> > >>> > Hi,
> > >>> >
> > >>> > I have 5 nodes and 4 resources configured.
> > >>> > I have configured constraint such that no two
> resources can be
> > >>> co-located.
> > >>> > I brought down a node (which happened to be DC). I
> was expecting
> > >the
> > >>> > resource on the failed node would be migrated to the
> 5th waiting
> > >node
> > >>> (that
> > >>> > is not running any resource).
> > >>> > However what happened was the failed node resource
> was started on
> > >another
> > >>> > active node (after stopping it's existing resource)
> and that
> > >node's
> > >>> > resource was moved to the waiting node.
> > >>> >
> > >>> > What could I be doing wrong?
> > >>> >
> > >>> > <nvpair id="cib-bootstrap-options-have-watchdog"
> value="true"
> > >>> > name="have-watchdog"/>
> > >>> > <nvpair id="cib-bootstrap-options-dc-version"
> > >value="1.1.14-5a6cdd1"
> > >>> > name="dc-version"/>
> > >>> > <nvpair
> id="cib-bootstrap-options-cluster-infrastructure"
> > >>> value="corosync"
> > >>> > name="cluster-infrastructure"/>
> > >>> > <nvpair id="cib-bootstrap-options-stonith-enabled"
> value="false"
> > >>> > name="stonith-enabled"/>
> > >>> > <nvpair id="cib-bootstrap-options-no-quorum-policy"
> value="ignore"
> > >>> > name="no-quorum-policy"/>
> > >>> > <nvpair
> id="cib-bootstrap-options-default-action-timeout"
> > >value="240"
> > >>> > name="default-action-timeout"/>
> > >>> > <nvpair id="cib-bootstrap-options-symmetric-cluster"
> value="false"
> > >>> > name="symmetric-cluster"/>
> > >>> >
> > >>> > # pcs constraint
> > >>> > Location Constraints:
> > >>> > Resource: cu_2
> > >>> > Enabled on: Redun_CU4_Wb30 (score:0)
> > >>> > Enabled on: Redund_CU2_WB30 (score:0)
> > >>> > Enabled on: Redund_CU3_WB30 (score:0)
> > >>> > Enabled on: Redund_CU5_WB30 (score:0)
> > >>> > Enabled on: Redund_CU1_WB30 (score:0)
> > >>> > Resource: cu_3
> > >>> > Enabled on: Redun_CU4_Wb30 (score:0)
> > >>> > Enabled on: Redund_CU2_WB30 (score:0)
> > >>> > Enabled on: Redund_CU3_WB30 (score:0)
> > >>> > Enabled on: Redund_CU5_WB30 (score:0)
> > >>> > Enabled on: Redund_CU1_WB30 (score:0)
> > >>> > Resource: cu_4
> > >>> > Enabled on: Redun_CU4_Wb30 (score:0)
> > >>> > Enabled on: Redund_CU2_WB30 (score:0)
> > >>> > Enabled on: Redund_CU3_WB30 (score:0)
> > >>> > Enabled on: Redund_CU5_WB30 (score:0)
> > >>> > Enabled on: Redund_CU1_WB30 (score:0)
> > >>> > Resource: cu_5
> > >>> > Enabled on: Redun_CU4_Wb30 (score:0)
> > >>> > Enabled on: Redund_CU2_WB30 (score:0)
> > >>> > Enabled on: Redund_CU3_WB30 (score:0)
> > >>> > Enabled on: Redund_CU5_WB30 (score:0)
> > >>> > Enabled on: Redund_CU1_WB30 (score:0)
> > >>> > Ordering Constraints:
> > >>> > Colocation Constraints:
> > >>> > cu_3 with cu_2 (score:-INFINITY)
> > >>> > cu_4 with cu_2 (score:-INFINITY)
> > >>> > cu_4 with cu_3 (score:-INFINITY)
> > >>> > cu_5 with cu_2 (score:-INFINITY)
> > >>> > cu_5 with cu_3 (score:-INFINITY)
> > >>> > cu_5 with cu_4 (score:-INFINITY)
> > >>> >
> > >>> > -Thanks
> > >>> > Nikhil
> > >>>
> > >>>
> > >>>
> >
> > Hi,
> >
> > use of utilization (balanced strategy) has one caveat:
> resources are
> > not moved just because of utilization of one node is less,
> when
> > nodes have the same allocation score for the resource.
> > So, after the simultaneus outage of two nodes in a 5-node
> cluster,
> > it may appear that one node runs two resources and two
> recovered
> > nodes run nothing.
> >
> > Original 'utilization' strategy only limits resource
> placement, it
> > is not considered when choosing a node for a resource.
> >
> > Vladislav
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