Devstack doesn't use gunicorn

[timmc-edx]

Unlike 2U's deployed environments, devstack uses Django's runserver command instead of gunicorn.

A/C:

• If feasible, switch devstack to use gunicorn
• If not, add docs on how to use gunicorn when desired, and why it's not the default

Notes:

• edx-platform's lms/docker_lms_gunicorn.py has a hardcoded workers = 17 which may not be appropriate for devstack. We may just be able to change it, depending on what actually uses this file these days.
• Can we still get autoreloading with gunicorn?

[robrap]

@timmc-edx: I know you've been experimenting with gunicorn in devstack. What's the status of that? Are there temporary docs for that that would be used as part of this ticket? Is there anything you could add as a comment here? Thank you.

[timmc-edx]

For the new codejail service, I'm fairly sure I could just switch over the Dockerfile to just use gunicorn for both the dev and prod targets. It should just work. However, I think the main limiting factor is that runserver gives us auto-reloading when code changes on disk, and gunicorn doesn't, out of the box. So that's probably the main thing to look into.

[robrap]

Thanks @timmc-edx. That is partially answering my question about what is different about with and without gunicorn, but I wasn't actually asking about codejail. I was asking because there is another issue in DD in the LMS that may require local testing with gunicorn, and I wanted to link to a document for that setup.

[timmc-edx]

Yeah, but that's the service I happen to know about. :-) I thought you were asking about why we couldn't switch over all services in devstack.

As for local testing with gunicorn in the LMS, I recommend e93d674 which is on the timmc/lms-gunicorn branch, itself based on the local-devstack branch. I don't have a proper document for it.

[robrap]

Right. This ticket is for docs, so it is ok that there aren’t any. Your link to the commit is great. If you have any other rough notes/thoughts that would be useful for someone else to pick this up, just add an additional comment on this ticket. Either way, this is great. Thank you.