Add RemoteSlurmJob to connect SLURMCluster to a remote Slurm cluster

Hello 👋 Thank you for considering this feature request 😃 I have been looking over dask-jobqueue (together with prefect) to allocate resources on a Slurm cluster I have access to. dask-jobqueue seems exactly what we’d need for this, thank you for maintaining it 🙇

Context

In the case where Slurm and a python process (script or notebook) are not running on the same host SlurmCluster will not be able to spawn any jobs and error.

Slurm added a REST API: https://slurm.schedmd.com/rest_api.html

Feature

Could we add a RemoteSlurmCluster and RemoteSlurmJob that largely extend SlurmCluster/SlurmJob and instead of using subprocess.Popen we’d do an HTTP request instead?

class RemoteSLURMJob(SLURMJob):
    @contextmanager
    def job_file(self):
        # we don't need the script file but only the script itself. to not alter `async def start(self):` we yield the script here.
        yield self.job_script()

    async def _submit_job(self, script):
        # formatting should be according to:
        # https://slurm.schedmd.com/rest_api.html#slurmctldSubmitJob
        return requests.post('slurm-url/jobs/submit')  # reach out to API

    def _job_id_from_submit_output(self, out):
        # out is the JSON output from _submit_job request.post
        # See https://slurm.schedmd.com/rest_api.html#v0.0.36_job_submission_response
        return out['job_id']

    @classmethod
    def _close_job(cls, job_id):
        # See: https://slurm.schedmd.com/rest_api.html#slurmctldCancelJob
        requests.delete(f'slurm-url/job/{job_id}')


class RemoteSLURMCluster(SLURMCluster):
    job_cls = RemoteSLURMJob

As far as I can tell this should be a drop-in replacement.

Thoughts? (tagging @mrocklin @lesteve for visibility, hope you would have time for a review.)

[AlexanderVanEck]

inside a docker container (on a login node I assume)

Yes - or at least somewhere where it can send/receive calls from the SLURM REST API. I would say “inside” the cluster.

[willirath]

This could be of interest as well: https://gist.github.com/willirath/2176a9fa792577b269cb393995f43dda

It’s ssh’ing back to the host system where srun etc are available.