How to use the command 'squeue' (with examples)

The squeue command is a powerful utility within the SLURM (Simple Linux Utility for Resource Management) workload manager. It allows users to view and manage jobs in the queue of a computing cluster. This command offers various options to filter and display job information, helping users understand the status and position of their jobs within the queue.

View the queue:

Code:

squeue

Motivation:

Using the squeue command without any arguments provides a straightforward and comprehensive view of all jobs currently queued and running in SLURM. This is especially useful for system administrators and researchers who need to monitor the overall status of workloads, ensuring efficient resource allocation and job scheduling.

Explanation:

• The command squeue by itself queries the SLURM job scheduling system to return a list of all current jobs, displaying their IDs, partitions, names, users, states, priority, and other relevant information. This gives a broad overview of the job landscape at any given time.

Example Output:

JOBID    PARTITION     NAME     USER   ST TIME NODES NODELIST(REASON)
123456   compute      myjob1   alice   R  10:34  2     compute-0
123457   compute      myjob2   bob     PD    0:00  1  (Priority)
123458   gpu          myjob3   charlie R   2:45  1     gpu-2

View jobs queued by a specific user:

Code:

squeue -u username

Motivation:

By specifying a particular username, the user can narrow down the list of jobs to only those submitted by a specific individual. This is useful for users who want to track their job submissions quickly without having to sift through the entire job queue, which can be massive in a busy environment.

Explanation:

• The -u option stands for ‘user’, and it is followed by the username. This argument tells squeue to filter the displayed jobs so that only those belonging to the specified user are shown. This is particularly handy for users managing multiple jobs and wanting to focus solely on their own tasks.

Example Output:

JOBID    PARTITION     NAME     USER   ST TIME NODES NODELIST(REASON)
123456   compute      myjob1   alice   R  10:34  2     compute-0

View the queue and refresh every 5 seconds:

Code:

squeue -i 5

Motivation:

Continuous monitoring of job submissions and their statuses can be crucial when managing large and complicated computational tasks. By watching updates reflected every few seconds, users can make decisions based on the real-time state of the queue. This option is excellent for hands-on monitoring during dynamic workloads.

Explanation:

• The -i option followed by a number specifies the ‘interval’ at which the command refreshes and re-executes, displaying updated information every specified number of seconds. Here, with 5, the user receives an automatic update every 5 seconds, ensuring they see the very latest statistics.

Example Output:

This will show outputs similar to those described in the previous examples, continuously updating every five seconds.

Every 5.0s: squeue
JOBID    PARTITION     NAME     USER   ST TIME NODES NODELIST(REASON)
123456   compute      myjob1   alice   R  10:34  2     compute-0
123457   compute      myjob2   bob     PD    0:00  1  (Priority)

View the queue with expected start times:

Code:

squeue --start

Motivation:

Understanding when jobs are likely to commence is crucial for planning and resource management. This can be especially important in high-demand environments where waiting times could affect project deadlines. This flag provides an estimate, empowering users and administrators to adjust their schedules and expectations based on probable job start times.

Explanation:

• The --start option adds a column to the squeue output, indicating when the jobs are expected to begin. This can help predict delays and manage components that might be time-sensitive, allowing for strategic adjustments.

Example Output:

JOBID    PARTITION     NAME     USER   ST TIME NODES  START_TIME
123456   compute      myjob1   alice   R  10:34  2     N/A
123457   compute      myjob2   bob     PD    0:00  1  2023-10-30T14:00:00

Conclusion:

The squeue command serves as an essential tool for interacting with a SLURM-managed computing cluster, providing users with detailed insights into queued jobs. Tailoring its options according to specific needs, such as viewing jobs by user, updating the queue dynamically, or estimating job start times, allows for efficient and informed management of computational resources. Whether for debugging, monitoring, or planning, understanding how to leverage squeue optimizes the day-to-day operations in high-performance computing environments.