Dockerized nginx is not starting

Docker container runs as long as the command you specify with CMD, ENTRTYPOINT or through the command line is running. In your case the service command finishes right away and the whole container is shut down.

One way to fix this is to start nginx directly from the command line (make sure you don't run it as a daemon).

Another option is to create a small script which starts the service and then sleeps forever. Something like:

#!/bin/bash
service nginx start
while true; do sleep 1d; done

and run this instead of directly running the service command.

A third option would be to use something like runit or similar program, instead of the normal service.

As of now, the official nginx image uses this to run nginx (see the Dockerfile):

CMD ["nginx", "-g", "daemon off;"]

In my case, this was enough to get it to start properly. There are tutorials online suggesting more awkward ways of accomplishing this but the above seems quite clean.