[slurm-users] Random "sbatch" failure: "Socket timed out on send/recv operation"

Marcus Wagner wagner at itc.rwth-aachen.de
Wed Jun 12 15:06:18 UTC 2019


we hit the same issue, up to 30.000 entries per day in the slurmctld log.

As we used SL6 the first time (Scientific Linux), we had massive 
problems with sssd, often crashing.
We therefore decided to get rid of sssd and manually fill /etc/passwd 
and /etc/groups via cronjob.

So, yes we have a ldap, but it can't be the issue in our case, since 
user and group lookups are done locally.


On 6/12/19 3:36 PM, Christopher Benjamin Coffey wrote:
> Hi, you may want to look into increasing the sssd cache length on the nodes, and improving the network connectivity to your ldap directory. I recall when playing with sssd in the past that it wasn't actually caching. Verify with tcpdump, and "ls -l" through a directory. Once the uid/gid is resolved, it shouldn't be hitting the directory anymore till the cache expires.
> Do the nodes NAT through the head node?
> Best,
> Chris
>> Christopher Coffey
> High-Performance Computing
> Northern Arizona University
> 928-523-1167
> On 6/12/19, 1:56 AM, "slurm-users on behalf of Bjørn-Helge Mevik" <slurm-users-bounces at lists.schedmd.com on behalf of b.h.mevik at usit.uio.no> wrote:
>      Another possible cause (we currently see it on one of our clusters):
>      delays in ldap lookups.
>      We have sssd on the machines, and occasionally, when sssd contacts the
>      ldap server, it takes 5 or 10 seconds (or even 15) before it gets an
>      answer.  If that happens because slurmctld is trying to look up some
>      user or group, etc, client commands depending on it will hang.  The
>      default message timeout is 10 seconds, so if the delay is more than
>      that, you get the timeout error.
>      We don't know why the delays are happening, but while we are debugging
>      it, we've increased the MessageTimeout, which seems to have reduced the
>      problem a bit.  We're also experimenting with GroupUpdateForce and
>      GroupUpdateTime to reduce the number of times slurmctld needs to ask
>      about groups, but I'm unsure how much that helps.
>      --
>      Bjørn-Helge Mevik, dr. scient,
>      Department for Research Computing, University of Oslo

Marcus Wagner, Dipl.-Inf.

IT Center
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wagner at itc.rwth-aachen.de

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