Ensure nginx master process stays running

Question

I am currently trying to setup a docker container using ubuntu:14.04 as my base image, with nginx and gunicorn/django/celery running inside. I am using supervisor to start all of the processes, and have tested to make sure gunicorn is relaunched when it goes down. However, I can't figure out how to do it with nginx.

My supervisord.conf for nginx is as follows:

[program:nginx]
command=nginx
autorestart=false

I have autorestart set to false because, from what I can tell, the nginx command simply starts the master process and worker processes, and then exits with status code 0. If I have autorestart set to true, it simply keeps trying to restart that nginx command, which will fail for subsequent retries because the master/worker processes are already running and bound to the port.

On the surface, this seems okay, because if I try and kill a worker process, the master will start another worker to take it's place. But how do I ensure the master process stays running as well?

Answer 1

You need to append daemon off; to your nginx.conf configuration instructing nginx to run in the foreground.

Then modify your supervisor stanza to be:

[program:nginx]
command=nginx
autorestart=true

It will still spawn master/worker processes/subprocesses and can be used this way in production setups just fine. In this case it's supervisor that runs the process in the background and controls and supervises it.

See this FAQ entry