I enabled "debug3" logging and saw this in the node log:

error: mpi_conf_send_stepd: unable to resolve MPI plugin offset from plugin_id=106. This error usually results from a job being submitted against an MPI plugin which was not compiled into slurmd but was for job submission command.

error: _send_slurmstepd_init: mpi_conf_send_stepd(9, 106) failed: No error

I removed "MpiDefault" option from slurm.conf and now "srun -N2 -l hostname" returns hostnames of all machines

On Tue, Jun 11, 2024 at 11:05 AM Arnuld <arnuld@aganitha.ai> wrote:

I have two machines. When I run "srum hostname" on one machine (it's both a controller and a node) then I get the hostname fine but I get socket timed out error in these two situations:

1) "srun hostname" on 2nd machine (it's a node)
2) "srun -N 2 hostname" on controller

"scontrol show node" shows both mach2 and mach4. "sinfo" shows both nodes too. Also the job gets stuck forever in CG state after the error. Here is the output:

$ srun -N 2 hostname
mach2
srun: error: slurm_receive_msgs: [[mach4]:6818] failed: Socket timed out on send/recv operation
srun: error: Task launch for StepId=2222.0 failed on node hpc4: Socket timed out on send/recv operation
srun: error: Application launch failed: Socket timed out on send/recv operation
srun: Job step aborted

Output form "squeue" 3 seconds apart

Tue Jun 11 05:09:56 2024
JOBID PARTITION NAME USER ST TIME NODES NODELIST(REASON)
2222 poxo hostname arnuld R 0:19 2 mach4,mach2

Tue Jun 11 05:09:59 2024
JOBID PARTITION NAME USER ST TIME NODES NODELIST(REASON)
2222 poxo hostname arnuld CG 0:20 1 mach4