On Fri, Dec 8, 2023 at 5:44 PM Artem <tyom...@gmail.com> wrote:
>
> Hello experts.
>
> I use pacemaker for a Lustre cluster. But for simplicity and exploration I
> use a Dummy resource. I didn't like how resource performed failover and
> failback. When I shut down VM with remote agent, pacemaker tries to restart
> it. According to pcs status it marks the resource (not RA) Online for some
> time while VM stays down.
>
> OK, I wanted to improve its behavior and set up a ping monitor. I tuned the
> scores like this:
> pcs resource create FAKE3 ocf:pacemaker:Dummy
> pcs resource create FAKE4 ocf:pacemaker:Dummy
> pcs constraint location FAKE3 prefers lustre3=100
> pcs constraint location FAKE3 prefers lustre4=90
> pcs constraint location FAKE4 prefers lustre3=90
> pcs constraint location FAKE4 prefers lustre4=100
> pcs resource defaults update resource-stickiness=110
> pcs resource create ping ocf:pacemaker:ping dampen=5s host_list=local op
> monitor interval=3s timeout=7s clone meta target-role="started"
> for i in lustre{1..4}; do pcs constraint location ping-clone prefers $i; done
> pcs constraint location FAKE3 rule score=0 pingd lt 1 or not_defined pingd
> pcs constraint location FAKE4 rule score=0 pingd lt 1 or not_defined pingd
> pcs constraint location FAKE3 rule score=125 pingd gt 0 or defined pingd
> pcs constraint location FAKE4 rule score=125 pingd gt 0 or defined pingd
>
These rules are contradicting. You set the score to 125 if pingd is
defined and at the same time set it to 0 if the score is less than 1.
To be "less than 1" it must be defined to start with so both rules
will always apply. I do not know how the rules are ordered. Either you
get random behavior, or one pair of these rules is effectively
ignored.
>
> Question #1) Why I cannot see accumulated score from pingd in crm_simulate
> output? Only location score and stickiness.
> pcmk__primitive_assign: FAKE3 allocation score on lustre3: 210
> pcmk__primitive_assign: FAKE3 allocation score on lustre4: 90
> pcmk__primitive_assign: FAKE4 allocation score on lustre3: 90
> pcmk__primitive_assign: FAKE4 allocation score on lustre4: 210
> Either when all is OK or when VM is down - score from pingd not added to
> total score of RA
>
>
> Question #2) I shut lustre3 VM down and leave it like that. pcs status:
> * FAKE3 (ocf::pacemaker:Dummy): Stopped
> * FAKE4 (ocf::pacemaker:Dummy): Started lustre4
> * Clone Set: ping-clone [ping]:
> * Started: [ lustre-mds1 lustre-mds2 lustre-mgs lustre1 lustre2 lustre4 ]
> << lustre3 missing
> OK for now
> VM boots up. pcs status:
> * FAKE3 (ocf::pacemaker:Dummy): FAILED (blocked) [ lustre3 lustre4 ]
> << what is it?
> * Clone Set: ping-clone [ping]:
> * ping (ocf::pacemaker:ping): FAILED lustre3 (blocked) << why
> not started?
> * Started: [ lustre-mds1 lustre-mds2 lustre-mgs lustre1 lustre2 lustre4 ]
If this is full pcs status output, I miss stonith resource.
> I checked server processes manually and found that lustre4 runs
> "/usr/lib/ocf/resource.d/pacemaker/ping monitor" while lustre3 doesn't
> All is according to documentation but results are strange.
> Then I tried to add meta target-role="started" to pcs resource create ping
> and this time ping started after node rebooted. Can I expect that it was just
> missing from official setup documentation, and now everything will work fine?
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