[slurm-users] [External] Hibernating a whole cluster

Analabha Roy hariseldon99 at gmail.com
Tue Feb 7 13:18:01 UTC 2023


On Tue, 7 Feb 2023, 18:12 Diego Zuccato, <diego.zuccato at unibo.it> wrote:

> RAM used by a suspended job is not released. At most it can be swapped
> out (if enough swap is available).
>


There should be enough swap available. I have 93 gigs of Ram and as big a
swap partition. I can top it off with swap files if needed.




>
> Il 07/02/2023 13:14, Analabha Roy ha scritto:
> > Hi Sean,
> >
> > Thanks for your awesome suggestion! I'm going through the reservation
> > docs now. At first glance, it seems like a daily reservation would turn
> > down jobs that are too big for the reservation. It'd be nice if
> > slurm could suspend (in the manner of 'scontrol suspend') jobs during
> > reserved downtime and resume them after. That way, folks can submit
> > large jobs without having to worry about the downtimes. Perhaps the FLEX
> > option in reservations can accomplish this somehow?
> >
> >
> > I suppose that I can do it using a shell script iterator and a cron job,
> > but that seems like an ugly hack. I was hoping if there is a way to
> > config this in slurm itself?
> >
> > AR
> >
> > On Tue, 7 Feb 2023 at 16:06, Sean Mc Grath <smcgrat at tcd.ie
> > <mailto:smcgrat at tcd.ie>> wrote:
> >
> >     Hi Analabha,
> >
> >     Could you do something like create a daily reservation for 8 hours
> >     that starts at 9am, or whatever times work for you like the
> >     following untested command:
> >
> >     scontrol create reservation starttime=09:00:00 duration=8:00:00
> >     nodecnt=1 flags=daily ReservationName=daily
> >
> >     Daily option at https://slurm.schedmd.com/scontrol.html#OPT_DAILY
> >     <https://slurm.schedmd.com/scontrol.html#OPT_DAILY>
> >
> >     Some more possible helpful documentation at
> >     https://slurm.schedmd.com/reservations.html
> >     <https://slurm.schedmd.com/reservations.html>, search for "daily".
> >
> >     My idea being that jobs can only run in that reservation, (that
> >     would have to be configured separately, not sure how from the top of
> >     my head), which is only active during the times you want the node to
> >     be working. So the cronjob that hibernates/shuts it down will do so
> >     when there are no jobs running. At least in theory.
> >
> >     Hope that helps.
> >
> >     Sean
> >
> >     ---
> >     Sean McGrath
> >     Senior Systems Administrator, IT Services
> >
> >
>  ------------------------------------------------------------------------
> >     *From:* slurm-users <slurm-users-bounces at lists.schedmd.com
> >     <mailto:slurm-users-bounces at lists.schedmd.com>> on behalf of
> >     Analabha Roy <hariseldon99 at gmail.com <mailto:hariseldon99 at gmail.com
> >>
> >     *Sent:* Tuesday 7 February 2023 10:05
> >     *To:* Slurm User Community List <slurm-users at lists.schedmd.com
> >     <mailto:slurm-users at lists.schedmd.com>>
> >     *Subject:* Re: [slurm-users] [External] Hibernating a whole cluster
> >     Hi,
> >
> >     Thanks. I had read the Slurm Power Saving Guide before. I believe
> >     the configs enable slurmctld to check other nodes for idleness and
> >     suspend/resume them. Slurmctld must run on a separate, always-on
> >     server for this to work, right?
> >
> >     My issue might be a little different. I literally have only one node
> >     that runs everything: slurmctld, slurmd, slurmdbd, everything.
> >
> >     This node must be set to "sudo systemctl hibernate"after business
> >     hours, regardless of whether jobs are queued or running. The next
> >     business day, it can be switched on manually.
> >
> >     systemctl hibernate is supposed to save the entire run state of the
> >     sole node to swap and poweroff. When powered on again, it should
> >     restore everything to its previous running state.
> >
> >     When the job queue is empty, this works well. I'm not sure how well
> >     this hibernate/resume will work with running jobs and would
> >     appreciate any suggestions or insights.
> >
> >     AR
> >
> >
> >     On Tue, 7 Feb 2023 at 01:39, Florian Zillner <fzillner at lenovo.com
> >     <mailto:fzillner at lenovo.com>> wrote:
> >
> >         Hi,
> >
> >         follow this guide: https://slurm.schedmd.com/power_save.html
> >         <https://slurm.schedmd.com/power_save.html>
> >
> >         Create poweroff / poweron scripts and configure slurm to do the
> >         poweroff after X minutes. Works well for us. Make sure to set an
> >         appropriate time (ResumeTimeout) to allow the node to come back
> >         to service.
> >         Note that we did not achieve good power saving with suspending
> >         the nodes, powering them off and on saves way more power. The
> >         downside is it takes ~ 5 mins to resume (= power on) the nodes
> >         when needed.
> >
> >         Cheers,
> >         Florian
> >
>  ------------------------------------------------------------------------
> >         *From:* slurm-users <slurm-users-bounces at lists.schedmd.com
> >         <mailto:slurm-users-bounces at lists.schedmd.com>> on behalf of
> >         Analabha Roy <hariseldon99 at gmail.com
> >         <mailto:hariseldon99 at gmail.com>>
> >         *Sent:* Monday, 6 February 2023 18:21
> >         *To:* slurm-users at lists.schedmd.com
> >         <mailto:slurm-users at lists.schedmd.com>
> >         <slurm-users at lists.schedmd.com
> >         <mailto:slurm-users at lists.schedmd.com>>
> >         *Subject:* [External] [slurm-users] Hibernating a whole cluster
> >         Hi,
> >
> >         I've just finished  setup of a single node "cluster" with slurm
> >         on ubuntu 20.04. Infrastructural limitations  prevent me from
> >         running it 24/7, and it's only powered on during business hours.
> >
> >
> >         Currently, I have a cron job running that hibernates that sole
> >         node before closing time.
> >
> >         The hibernation is done with standard systemd, and hibernates to
> >         the swap partition.
> >
> >           I have not run any lengthy slurm jobs on it yet. Before I do,
> >         can I get some thoughts on a couple of things?
> >
> >         If it hibernated when slurm still had jobs running/queued, would
> >         they resume properly when the machine powers back on?
> >
> >         Note that my swap space is bigger than my  RAM.
> >
> >         Is it necessary to perhaps setup a pre-hibernate script for
> >         systemd to  iterate scontrol to suspend all the jobs before
> >         hibernating and resume them post-resume?
> >
> >         What about the wall times? I'm uessing that slurm will count the
> >         downtime as elapsed for each job. Is there a way to config this,
> >         or is the only alternative a post-hibernate script that
> >         iteratively updates the wall times of the running jobs using
> >         scontrol again?
> >
> >         Thanks for your attention.
> >         Regards
> >         AR
> >
> >
> >
> >     --
> >     Analabha Roy
> >     Assistant Professor
> >     Department of Physics
> >     <http://www.buruniv.ac.in/academics/department/physics>
> >     The University of Burdwan <http://www.buruniv.ac.in/>
> >     Golapbag Campus, Barddhaman 713104
> >     West Bengal, India
> >     Emails: daneel at utexas.edu <mailto:daneel at utexas.edu>,
> >     aroy at phys.buruniv.ac.in <mailto:aroy at phys.buruniv.ac.in>,
> >     hariseldon99 at gmail.com <mailto:hariseldon99 at gmail.com>
> >     Webpage: http://www.ph.utexas.edu/~daneel/
> >     <http://www.ph.utexas.edu/~daneel/>
> >
> >
> >
> > --
> > Analabha Roy
> > Assistant Professor
> > Department of Physics
> > <http://www.buruniv.ac.in/academics/department/physics>
> > The University of Burdwan <http://www.buruniv.ac.in/>
> > Golapbag Campus, Barddhaman 713104
> > West Bengal, India
> > Emails: daneel at utexas.edu <mailto:daneel at utexas.edu>,
> > aroy at phys.buruniv.ac.in <mailto:aroy at phys.buruniv.ac.in>,
> > hariseldon99 at gmail.com <mailto:hariseldon99 at gmail.com>
> > Webpage: http://www.ph.utexas.edu/~daneel/
> > <http://www.ph.utexas.edu/~daneel/>
>
> --
> Diego Zuccato
> DIFA - Dip. di Fisica e Astronomia
> Servizi Informatici
> Alma Mater Studiorum - Università di Bologna
> V.le Berti-Pichat 6/2 - 40127 Bologna - Italy
> tel.: +39 051 20 95786
>
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