Dear slurm-user list,

currently, I am seeing the same issue again and again; maybe like once a week. Where when a user stops a nextflow run, terminating many jobs at the same time, the system puts nodes in drain saying they did not stop in time ("drained" "Kill task failed").

Looking at the slurmd log files indicate that not stopping the job, but removing the job's step cgroup is the issue:

[2026-08-18T14:12:44.729] [251978.batch] debug2: cgroup/v2: cgroup_p_step_destroy: still unable to remove job's step cgroup (/sys/fs/cgroup/system.slice/slurmstepd.scope/job_251978): Device or resource busy
[2026-08-18T14:12:44.730] [251978.extern] debug2: proctrack/cgroup: proctrack_p_signal: sending process 160348 (slurm_task) signal 15
[2026-08-18T14:12:49.197] [251982.extern] debug2: proctrack/cgroup: proctrack_p_signal: sending process 160672 (slurm_task) signal 18
[2026-08-18T14:12:49.216] [251982.batch] debug2: cgroup/v2: cgroup_p_step_destroy: still unable to remove job's step cgroup (/sys/fs/cgroup/system.slice/slurmstepd.scope/job_251982): Device or resource busy
[2026-08-18T14:12:49.217] [251982.extern] debug2: proctrack/cgroup: proctrack_p_signal: sending process 160672 (slurm_task) signal 15
[2026-08-18T15:53:27.057] [252037.extern] debug2: proctrack/cgroup: proctrack_p_signal: sending process 166993 (slurm_task) signal 18

My cgroup.conf:

CgroupMountpoint="/sys/fs/cgroup"
ConstrainCores=no
ConstrainRAMSpace=yes
ConstrainSwapSpace=no
ConstrainDevices=no
AllowedRamSpace=100
AllowedSwapSpace=0
MaxRAMPercent=100
MaxSwapPercent=100

From slurm.conf:

ProctrackType=proctrack/cgroup
TaskPlugin=task/cgroup

Slurm Version: slurm 24.11.3

As I often recognize this issue after it occurs, I cannot really debug during the removal attempt and I am unsure how to debug this issue further. I am thankful for any ideas!

Best,
Xaver