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

The ‘slurmrestd’ command is an interface to Slurm, a workload manager used in high-performance computing clusters, via the REST API. It can be used in two modes: Inetd Mode and Listen Mode. ‘slurmrestd’ allows users to interact with Slurm by sending HTTP requests to the REST API endpoints provided by the command.

Use case 1: Change the group ID (and drop supplemental groups) before processing client requests

Code:

slurmrestd --g group_id [host]:port | unix:/path/to/socket

Motivation: The ‘–g’ option in ‘slurmrestd’ allows users to specify a group ID to switch to before processing client requests. This is useful for ensuring that the command has the appropriate permissions and access to resources associated with the specified group.

Explanation:

• ‘–g group_id’: Specifies the group ID to switch to before processing client requests.
• ‘[host]:port | unix:/path/to/socket’: Specifies the host and port or Unix socket path where the ‘slurmrestd’ service is running.

Example output: No output is produced when using this command.

Use case 2: Comma-delimited list of authentication plugins to load

Code:

slurmrestd -a authentication_plugins [host]:port | unix:/path/to/socket

Motivation: The ‘-a’ option in ‘slurmrestd’ allows users to specify a comma-delimited list of authentication plugins to load. This is useful for customizing the authentication mechanism used by the ‘slurmrestd’ service to verify the identity of clients.

Explanation:

• ‘-a authentication_plugins’: Specifies the comma-delimited list of authentication plugins to load.
• ‘[host]:port | unix:/path/to/socket’: Specifies the host and port or Unix socket path where the ‘slurmrestd’ service is running.

Example output: No output is produced when using this command.

Use case 3: Read Slurm configuration from the specified file

Code:

slurmrestd -f path/to/file

Motivation: The ‘-f’ option in ‘slurmrestd’ allows users to specify the path to a file from which Slurm’s configuration should be read. This is useful for overriding the default configuration settings of Slurm and using a custom configuration file instead.

Explanation:

• ‘-f path/to/file’: Specifies the path to the file from which Slurm’s configuration should be read.

Example output: No output is produced when using this command.

Use case 4: Change user ID before processing client request

Code:

slurmrestd -u user_id

Motivation: The ‘-u’ option in ‘slurmrestd’ allows users to specify a user ID to switch to before processing client requests. This is useful for ensuring that the command has the appropriate permissions and access to resources associated with the specified user.

Explanation:

• ‘-u user_id’: Specifies the user ID to switch to before processing client requests.

Example output: No output is produced when using this command.

Use case 5: Display help

Code:

slurmrestd -h

Motivation: The ‘-h’ option in ‘slurmrestd’ displays the help message, providing users with information about the available options and usage of the command. This is useful for learning how to use ‘slurmrestd’ effectively.

Explanation:

• ‘-h’: Displays the help message.

Example output:

Usage: slurmrestd [-u user_id] [-g group_id] [-a authentication_plugins] [-f
          path/to/file] [host[:port] | unix:/path/to/socket]
...

Use case 6: Display version

Code:

slurmrestd -V

Motivation: The ‘-V’ option in ‘slurmrestd’ displays the version number of the command. This is useful for checking the current version and ensuring compatibility with other components in the Slurm ecosystem.

Explanation:

• ‘-V’: Displays the version number.

Example output:

slurmrestd 21.08 (slurm 21.08.0)

Conclusion

The ‘slurmrestd’ command provides a simple and convenient way to interact with Slurm via the REST API. The various options available allow users to customize the behavior of the command based on their requirements. By understanding the different use cases of ‘slurmrestd’, users can effectively leverage its capabilities to manage their workload in high-performance computing clusters.