We're running nscd on all nodes, with an extremely stable list of
users/accounts, so I think we should be good here.
Don't bet on it. I've had issues in the past with nscd in similar
situations to this. There's a reason that daemon has a "paranoid" option.
Hostname should be completely local and not use any nameservices like
DNS or nscd in the first place, though. But just to be sure, what if you
ran a command like 'srun ls -ld /etc' I just chose /etc because every
Unix/Linux system should have that directory and it should be on the
local system disk, and -d so that the output will be only one line. An
ls on any single file or dir that's on all systems should work. or 'srun
date' should be pretty safe from 'outside forces'.
Prentice
On 4/26/19 11:24 AM, Andy Riebs wrote:
Hi John,
> It's a DNS problem, isn't it? Seriously though - how long does
srun hostname take for a single system?
We're running nscd on all nodes, with an extremely stable list of
users/accounts, so I think we should be good here.
"time srun hostname" reports on the order of 0.2 seconds, so at least
single node requests are handled expediently!
Andy
------------------------------------------------------------------------
*From:* John Hearns <hear...@googlemail.com>
*Sent:* Friday, April 26, 2019 10:56AM
*To:* Slurm User Community List <slurm-users@lists.schedmd.com>
*Cc:*
*Subject:* Re: [slurm-users] job startup timeouts?
It's a DNS problem, isn't it? Seriously though - how long does srun
hostname take for a single system?
On Fri, 26 Apr 2019 at 15:49, Douglas Jacobsen <dmjacob...@lbl.gov
<mailto:dmjacob...@lbl.gov>> wrote:
We have 12,000 nodes in our system, 9,600 of which are KNL. We can
start a parallel application within a few seconds in most cases (when
the machine is dedicated to this task), even at full scale. So I
don't think there is anything intrinsic to Slurm that would
necessarily be limiting you, though we have seen cases in the past
where arbitrary task distribution has caused contoller slow-down
issues as the detailed scheme was parsed.
Do you know if all the slurmstepd's are starting quickly on the
compute nodes? How is the OS/Slurm/executable delivered to the node?
----
Doug Jacobsen, Ph.D.
NERSC Computer Systems Engineer
Acting Group Lead, Computational Systems Group
National Energy Research Scientific Computing Center
dmjacob...@lbl.gov <mailto:dmjacob...@lbl.gov>
------------- __o
---------- _ '\<,_
----------(_)/ (_)__________________________
On Fri, Apr 26, 2019 at 7:40 AM Riebs, Andy <andy.ri...@hpe.com
<mailto:andy.ri...@hpe.com>> wrote:
>
> Thanks for the quick response Doug!
>
> Unfortunately, I can't be specific about the cluster size, other
than to say it's got more than a thousand nodes.
>
> In a separate test that I had missed, even "srun hostname" took
5 minutes to run. So there was no remote file system or MPI
involvement.
>
> Andy
>
> -----Original Message-----
> From: slurm-users [mailto:slurm-users-boun...@lists.schedmd.com
<mailto:slurm-users-boun...@lists.schedmd.com>] On Behalf Of
Douglas Jacobsen
> Sent: Friday, April 26, 2019 9:24 AM
> To: Slurm User Community List <slurm-users@lists.schedmd.com
<mailto:slurm-users@lists.schedmd.com>>
> Subject: Re: [slurm-users] job startup timeouts?
>
> How large is very large? Where is the executable being started? In
> the parallel filesystem/NFS? If that is the case you may be able to
> trim start times by using sbcast to transfer the executable (and its
> dependencies if dynamically linked) into a node-local resource, such
> as /tmp or /dev/shm depending on your local configuration.
> ----
> Doug Jacobsen, Ph.D.
> NERSC Computer Systems Engineer
> Acting Group Lead, Computational Systems Group
> National Energy Research Scientific Computing Center
> dmjacob...@lbl.gov <mailto:dmjacob...@lbl.gov>
>
> ------------- __o
> ---------- _ '\<,_
> ----------(_)/ (_)__________________________
>
>
> On Fri, Apr 26, 2019 at 5:34 AM Andy Riebs <andy.ri...@hpe.com
<mailto:andy.ri...@hpe.com>> wrote:
> >
> > Hi All,
> >
> > We've got a very large x86_64 cluster with lots of cores on
each node, and hyper-threading enabled. We're running Slurm
18.08.7 with Open MPI 4.x on CentOS 7.6.
> >
> > We have a job that reports
> >
> > srun: error: timeout waiting for task launch, started 0 of
xxxxxx tasks
> > srun: Job step 291963.0 aborted before step completely launched.
> >
> > when we try to run it at large scale. We anticipate that it
could take as long as 15 minutes for the job to launch, based on
our experience with smaller numbers of nodes.
> >
> > Is there a timeout setting that we're missing that can be
changed to accommodate a lengthy startup time like this?
> >
> > Andy
> >
> > --
> >
> > Andy Riebs
> > andy.ri...@hpe.com <mailto:andy.ri...@hpe.com>
> > Hewlett-Packard Enterprise
> > High Performance Computing Software Engineering
> > +1 404 648 9024
> > My opinions are not necessarily those of HPE
> > May the source be with you!
>
