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