Slurm Print Output While Running

Caroline Mae

2 min read

·

01-01-2025

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Submitting a large job to Slurm can leave you feeling in the dark, wondering about its progress. Fortunately, there are several ways to monitor your Slurm jobs and see their output while they're running, preventing unnecessary anxiety and allowing for proactive intervention if necessary. This guide provides a breakdown of effective methods.

Understanding Slurm Job States

Before diving into output monitoring, it's crucial to grasp Slurm's job states. Understanding these states will help you interpret the information you see during monitoring. Key states include:

• PENDING: Your job is waiting for resources.
• RUNNING: Your job is currently executing.
• COMPLETED: Your job finished successfully.
• FAILED: Your job encountered an error and terminated.
• CANCELLED: Your job was manually cancelled.

Methods for Monitoring Slurm Output During Execution

Several methods allow you to view the standard output and error streams of your Slurm job while it's running. Choosing the best method depends on your preference and the size of the output:

1. scontrol show job <job_id>

This command provides a summary of your job's status, including its current state, nodes used, and other relevant information. While it doesn't display the full output stream in real-time, it gives a valuable overview of your job's progress. This is particularly useful for checking if the job has started, is progressing smoothly, or has encountered problems.

2. squeue -u <username>

This command shows all your currently running and pending jobs. While it doesn't show the output itself, it provides valuable information about the state and progress of your jobs. You can check the job ID here before employing other monitoring techniques.

3. Tailing the output file with tail -f

This is a powerful method for monitoring real-time output. When submitting your Slurm job, you should specify an output file (e.g., -o output.txt). Then, you can use the tail -f command to monitor the file as it's being written to:

tail -f output.txt

The -f option ensures that tail continues to display new lines as they are added to the file. This offers a dynamic view of your job's progress and any messages it generates.

4. Using srun with output redirection

You can leverage the srun command to directly capture output during execution. This is particularly helpful for interactive jobs or situations where you want the output to be displayed immediately as the script runs:

srun -o output.txt your_command

This command executes your_command and redirects the standard output to output.txt. It doesn't require post-processing to access the output.

5. Slurm web portals (if available)

Many HPC clusters offer web-based Slurm portals. These portals provide a user-friendly interface for managing and monitoring jobs, often including real-time output viewing capabilities. Check with your system administrator to see if such a portal is available at your institution.

Best Practices for Monitoring Slurm Jobs

• Regularly check your job's status: Use squeue or the web portal to get updates on your job's progress.
• Properly configure output redirection: Always specify output and error files to avoid losing valuable information.
• Use appropriate monitoring tools: Choose a method that suits the size and nature of your job's output.
• Understand your job's expected runtime: This helps you determine if it's taking unusually long and if further investigation is required.

By utilizing these methods and best practices, you can efficiently monitor your Slurm jobs and gain valuable insights into their execution, leading to improved productivity and reduced troubleshooting time.