[slurm-users] Nodes stay drained no matter what I do

[Groner, Rob]

Ya, I agree about the invalid argument not being much help.

In times past when I encountered issues like that, I typically tried:

  *   restart slurmd on the compute node.  Watch its log to see what it complains about.  Usually it's about memory.
  *   Set the configuration of the node to whatever slurmd -C says, or set config_overrides in slurm.conf

Rob

________________________________
From: slurm-users <slurm-users-bounces at lists.schedmd.com> on behalf of Patrick Goetz <pgoetz at math.utexas.edu>
Sent: Thursday, August 24, 2023 11:27 AM
To: Slurm User Community List <slurm-users at lists.schedmd.com>
Subject: [slurm-users] Nodes stay drained no matter what I do


Master/Nodes: Ubuntu 20.04, Slurm 19.05.5 (as packaged by Debian)

This is an upgrade from a working Ubuntu 18.04/Slurm 17.x system where I
re-used the original slurm.conf (fearing this might cause issues).  The
hardware is the same.  The Master and nodes all use the same slurm.conf,
gres.conf, and cgroup.conf files which are soft linked into
/etc/slurm-llnl from an NFS mounted filesystem.

As per the subject, the nodes refuse to revert to idle:

-----------------------------------------------------------
root at hypnotoad:~# sinfo -N -l
Thu Aug 24 10:01:20 2023
NODELIST   NODES PARTITION       STATE CPUS    S:C:T MEMORY TMP_DISK
WEIGHT AVAIL_FE REASON
dgx-2          1       dgx     drained   80   80:1:1 500000        0
  1   (null) gres/gpu count repor
dgx-3          1       dgx     drained   80   80:1:1 500000        0
  1   (null) gres/gpu count repor
dgx-4          1       dgx     drained   80   80:1:1 500000        0
  1   (null) gres/gpu count
...
titan-3        1   titans*     drained   40   40:1:1 250000        0
  1   (null) gres/gpu count report
...
-----------------------------------------------------------

Neither of these commands has any effect:

   scontrol update NodeName=dgx-[2-6] State=RESUME
   scontrol update state=idle nodename=dgx-[2-6]


When I check the slurmctld log I find this helpful information:

-----------------------------------------------------------
...
[2023-08-24T00:00:00.033] error: _slurm_rpc_node_registration
node=dgx-4: Invalid argument
[2023-08-24T00:00:00.037] error: _slurm_rpc_node_registration
node=dgx-2: Invalid argument
[2023-08-24T00:00:00.216] error: _slurm_rpc_node_registration
node=titan-12: Invalid argument
[2023-08-24T00:00:00.216] error: _slurm_rpc_node_registration
node=titan-11: Invalid argument
[2023-08-24T00:00:00.266] error: _slurm_rpc_node_registration
node=dgx-6: Invalid argument
...
-----------------------------------------------------------

Googling, this appears to indicate that there is a resource mismatch
between the actual hardware and what is specified in slurm.conf. Note
that the existing configuration worked for Slurm 17, but I checked, and
it looks fine to me:

Relevant parts of slurm.conf:

-----------------------------------------------------------
   SchedulerType=sched/backfill
   SelectType=select/cons_res
   SelectTypeParameters=CR_Core_Memory

   PartitionName=titans Default=YES Nodes=titan-[3-15] State=UP
MaxTime=UNLIMITED
   PartitionName=dgx Nodes=dgx-[2-6] State=UP MaxTime=UNLIMITED

   GresTypes=gpu
   NodeName=titan-[3-15] Gres=gpu:titanv:8 RealMemory=250000 CPUs=40
   NodeName=dgx-2 Gres=gpu:tesla-v100:7 RealMemory=500000 CPUs=80
   NodeName=dgx-[3-6] Gres=gpu:tesla-v100:8 RealMemory=500000 CPUs=80
-----------------------------------------------------------

All the nodes in the titan partition are identical hardware, as are the
nodes in the dgx partition save for dgx-2, which lost a GPU and is no
longer under warranty.  So, using a couple of representative nodes:

root at dgx-4:~# slurmd -C
NodeName=dgx-4 CPUs=80 Boards=1 SocketsPerBoard=2 CoresPerSocket=20
ThreadsPerCore=2 RealMemory=515846

root at titan-8:~# slurmd -C
NodeName=titan-8 CPUs=40 Boards=1 SocketsPerBoard=2 CoresPerSocket=10
ThreadsPerCore=2 RealMemory=257811


I'm at a loss for how to debug this and am looking suggestions. Since
the resources on these machines are strictly dedicated to Slurm jobs,
would it be best to use the output of `slurmd -C` directly for the right
hand side of NodeName, reducing the memory a bit for OS overhead? Is
there any way to get better debugging output? "Invalid argument" doesn't
tell me much.

Thanks.







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