Managing and Canceling Jobs

Last updated on 2026-08-24 | Edit this page

Estimated time: 20 minutes

Overview

Questions

  • How do I cancel a running or queued job?
  • What do I do when a job is stuck pending?
  • How do I troubleshoot common job failures?

Objectives

  • Use scancel to cancel jobs safely
  • Diagnose why jobs are stuck in PENDING state
  • Troubleshoot timeout, out-of-memory, and other common failures

Canceling Jobs with scancel

Cancel a Single Job

BASH 

scancel 12345

The job stops immediately. Output files written so far are preserved.

Cancel Multiple Jobs

BASH 

# Cancel all your jobs
scancel -u $USER

# Cancel by name
scancel --name=test

# Cancel only pending jobs
scancel --state=PENDING -u $USER

# Cancel by partition
scancel -u $USER --partition=amd
Callout

Be Careful with scancel

Cancellation is immediate and irreversible. Before canceling: 1. Verify the job ID: squeue -j 12345 2. Consider if partial results should be saved 3. Never use scancel -u $USER unless you intend to cancel everything

A safer approach:

BASH 

# Preview what will be cancelled
squeue -u $USER --name=test_job
# Then cancel
scancel --name=test_job

Troubleshooting: Job Stuck in PENDING

Check the reason:

BASH 

squeue -j JOBID -O jobid,reason
Reason Meaning Solution
Resources No suitable node available Reduce resource requests or wait
QOSMaxPerUser Hit quota Wait for other jobs to finish
ReqNodeNotAvail Requested node is down Remove -w flag; let SLURM choose

Troubleshooting: Job Failures

TIMEOUT (exit code 143)

Job exceeded the --time limit.

BASH 

seff JOBID | grep "Job Wall-clock time"
# Resubmit with more time
sbatch --time=08:00:00 script.sh

OUT OF MEMORY

Output contains “Killed” or “Memory limit exceeded.”

BASH 

seff JOBID | grep "Memory"
# Resubmit with more RAM
sbatch --mem=64G script.sh

FAILED (non-zero exit code)

Your code had an error, not a SLURM problem.

BASH 

cat slurm-JOBID.out
cat slurm-JOBID.err
# Fix the error in your code, then resubmit

“Module not found”

Ensure your shebang has the -l flag:

BASH 

#!/bin/bash -l    # MUST have -l

Or explicitly source the module environment:

BASH 

source /etc/profile
module load miniconda3
Challenge

Challenge 1: Cancel Practice

  1. Submit a long-running job:

    BASH 

    sbatch --time=01:00:00 -p amd --wrap="sleep 3600"

  2. Verify it is running: squeue -u $USER

  3. Cancel it: scancel JOBID

  4. Verify cancellation: squeue -u $USER

  5. Check history: sacct -j JOBID --format=jobid,state,exitcode

You should see STATE=CANCELLED.

After canceling, squeue no longer shows the job. sacct shows STATE=CANCELLED with exit code 0:0, because cancellation is not a failure – the job simply did not run to completion.

Key Points
  • Use scancel JOBID to cancel a specific job; scancel -u $USER cancels all your jobs
  • Always verify the job ID before canceling
  • Pending jobs: check reason with squeue -O reason
  • Timeout: increase --time; OOM: increase --mem
  • Script errors show as FAILED with non-zero exit code; check output files
  • Ensure #!/bin/bash -l so modules load correctly in batch scripts