Using the 'strigger' Command in Slurm (with examples)

The ‘strigger’ command in Slurm is a useful tool for managing and automating tasks in high-performance computing clusters. It allows users to set, view, and clear triggers—actions that are automatically executed when specified events occur in the Slurm workload manager. This ability to automate responses to key events can significantly enhance the efficiency and reliability of workflows in a Slurm environment.

Use case 1: Registering a New Trigger

Code:

strigger --set --primary_slurmctld_failure --program=/path/to/executable

Motivation:
In a Slurm-managed cluster, ensuring the availability and reliability of critical components like the Slurm Controller Daemon (slurmctld) is vital. If the slurmctld fails, it could lead to downtime or loss of job control. Setting a trigger to execute a recovery script or notification program can automate the initial response to such failure events, enhancing system resilience.

Explanation:

• --set: This flag instructs ‘strigger’ to create a new trigger.
• --primary_slurmctld_failure: This specifies that the trigger should activate if the primary slurmctld fails.
• --program=/path/to/executable: This parameter designates the executable file to run when the trigger is activated. The path should point to a script or program tailored to handle the specific failure.

Example Output:
When this trigger is registered successfully, you will not see any standard output, but the system logs will indicate the registration of a new trigger for slurmctld failure. If the failure occurs, the specified executable will run, and you may receive logs or notifications depending on how you’ve configured your executable.

Use case 2: Executing a Program When a Specified Job Terminates

Code:

strigger --set --jobid=12345 --fini --program="/path/to/executable arg1 arg2"

Motivation:
Monitoring the completion of specific jobs can be important for users needing to collate results or chain subsequent job executions based on the outcome of the previous jobs. By executing a custom script when a job finishes (either successfully or unsuccessfully), one can automate data processing, notifications, or resubmissions.

Explanation:

• --set: Indicates the creation of a new trigger.
• --jobid=12345: Specifies the ID of the job to monitor for termination.
• --fini: This indicates the trigger should execute when the job finishes.
• --program="/path/to/executable arg1 arg2": Points to the script or program to execute upon job termination, along with any required arguments.

Example Output:
The trigger does not produce direct output upon setting. However, upon job termination, this action will execute the specified program. Logs of the program’s execution will depend on how the executable handles output.

Use case 3: Viewing Active Triggers

Code:

strigger --get

Motivation:
System administrators and users often need to audit or review which triggers are active within the system to ensure correct workflow automation and to troubleshoot potential issues. Viewing all active triggers provides insight into what actions are being monitored and can help identify unnecessary or misconfigured triggers.

Explanation:

• --get: This flag directs ‘strigger’ to retrieve information regarding all currently active triggers within the system.

Example Output:
The output lists all active triggers, showing information such as trigger IDs, event types, associated programs, and any specific conditions (like job IDs).

Use case 4: Viewing Active Triggers for a Specific Job

Code:

strigger --get --jobid=12345

Motivation:
When debugging or assessing job performance, it can be useful to review the triggers specifically tied to a single job. This focused inspection can reveal why certain actions were or weren’t performed in connection with a job’s lifecycle.

Explanation:

• --get: Used to retrieve trigger information.
• --jobid=12345: Specifies which job’s triggers to display, helping narrow down the information to only what’s relevant.

Example Output:
Returns details of triggers associated with job ID 12345, including when and how these triggers might be executed.

Use case 5: Clearing a Specified Trigger

Code:

strigger --clear 67890

Motivation:
Over time, certain triggers may become obsolete or need reconfiguration. Clearing an unnecessary or outdated trigger ensures that the system’s resources are optimally managed and that unintended actions aren’t taken.

Explanation:

• --clear: This option removes a trigger from the list of active triggers.
• 67890: This is the unique ID of the trigger you wish to clear from the system.

Example Output:
A confirmation message typically indicates successful trigger clearance, although direct output may depend on system configurations.

Conclusion:

The ‘strigger’ command offers robust options for automating, monitoring, and customizing responses to events within a Slurm managed environment. Whether ensuring system resilience, streamlining job workflows, or maintaining a clean slate of active triggers, understanding and implementing these use cases can greatly enhance the efficiency and reliability of your computing operations.