Some thoughts on moving from Torque to Slurm

This is more about the process than the feature set.

Torque moved out of open-source space a couple of years ago. This summer we are finally make the full shift to Slurm. I’m not going to trash the old thing here. Instead I want to celebrate the new thing and reflect on the process of installing it.

  1. I haven’t researched the progeny of Slurm as a project, but the UI seems engineered to make this shift easier. There are tables all over the Internet (including on our wiki!) of the Torque<->Slurm translations.
  2. Slurm’s accounting features were the trickiest part of this all to configure, but taking the time was worth it. Even at the testing stage, the sacct command’s output is super-informative.
  3. SchedMD’s documentation is among the best of any large piece of software I’ve worked with. If you’re doing this and you feel like you’re missing something, double-check their documents before flogging Stack Overflow etc.
  4. You can in fact do a single-server install as well as a cluster install. We did both, the latter in conjunction with Ansible. Neither is actually much more difficult than the other. That’s because the same three pieces of software (the controller, the database, and the worker daemon) have to run no matter the topology. It’s just that the worker runs on every compute node while the controller and database run only on the head node.
  5. We’ve been successful in using an A –> AB –> B approach to this transition. Right now we have both schedulers next to each other on each of these systems. That will remain the case for a few weeks, until we confirm we’ve done Slurm right.
  6. Schedulers have the most complicated build process of any piece of software I’ve worked with – except gcc, the building of which sometimes makes one want to walk into the ocean.
  7. Dependencies and related programs (e.g. your choice of email tool) are as much a complexity as the scheduler itself.
  8. From a branding perspective, Slurm managed to pull off an impressive feat. Its name is clear and distinctive in the software space, but a fun Easter egg if you have a certain geek pop culture interest/awareness.

This is has been successful up to now. We’ve soft-launched Slurm installs on our scientific computing servers. We should be all-Slurm when classes and researchers return.