[slurm-users] How to queue jobs based on non-existent features

[Raj Sahae]

Hi Brian and Paul,

You both sent me suggestions about using an offline dummy node with all features set. Thanks for your ideas but this won’t work for me as it’s not practical. We want to allow users to queue for all supported software versions and that easily numbers in the thousands or tens of thousands (every branch, every commit). If I could make this solution work, I would simply set the Available features for all nodes but this feels like it won’t scale well, or is an improper use of the Feature capability.

Thanks,

Raj Sahae | m. +1 (408) 230-8531

From: Raj Sahae <rsahae at tesla.com>
Date: Thursday, July 9, 2020 at 4:15 PM
To: "slurm-users at schedmd.com" <slurm-users at schedmd.com>
Subject: How to queue jobs based on non-existent features

Hi all,

My apologies if this is sent twice. The first time I sent it without my subscription to the list being complete.

I am attempting to use Slurm as a test automation system for its fairly advanced queueing and job control abilities, and also because it scales very well.
However, since our use case is a bit outside the standard usage of Slurm, we are hitting some issues that don’t appear to have obvious solutions.

In our current setup, the Slurm nodes are hosts attached to a test system. Our pipeline (greatly simplified) would be to install some software on the test system and then run sets of tests against it.
In our old pipeline, this was done in a single job, however with Slurm I was hoping to decouple these two actions as it makes the entire pipeline more robust to update failures and would give us more finely grained job control for the actual test run.

I would like to allow users to queue jobs with constraints indicating which software version they need. Then separately some automated job would scan the queue, see jobs that are not being allocated due to missing resources, and queue software installs appropriately. We attempted to do this using the Active/Available Features configuration. We use HealthCheck and Epilog scripts to scrape the test system for software properties (version, commit, etc.) and assign them as Features. Once an install is complete and the Features are updated, queued jobs would start to be allocated on those nodes.

Herein lies the conundrum. If a user submits a job, constraining to run on Version A, but all nodes in the cluster are currently configured with Features=Version-B, Slurm will fail to queue the job, indicating an invalid feature specification. I completely understand why Features are implemented this way, so my question is, is there some workaround or other Slurm capabilities that I could use to achieve this behavior? Otherwise my options seem to be:

  1.  Go back to how we did it before. The pipeline would have the same level of robustness as before but at least we would still be able to leverage other queueing capabilities of Slurm.
  2.  Write our own Feature or Job Submit plugin that customizes this behavior just for us. Seems possible but adds lead time and complexity to the situation.

It's not feasible to update the config for all branches/versions/commits to be AvailableFeatures, as our branch ecosystem is quite large and the maintenance of that approach would not scale well.

Thanks,

Raj Sahae  |  Manager, Software QA
3500 Deer Creek Rd, Palo Alto, CA 94304
m. +1 (408) 230-8531  | rsahae at tesla.com<file:///composeviewinternalloadurl/%3Cmailto:rsahae@tesla.com%3E>

[cid:image001.png at 01D6569E.6E58E770]<http://www.tesla.com/>

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