How to run Nginx within a Docker container without

Question

I have Nginx installed on a Docker container, and am trying to run it like this:

docker run -i -t -p 80:80 mydockerimage /usr/sbin/nginx

The problem is that the way Nginx works, is that the initial process immediately spawns a master Nginx process and some workers, and then quits. Since Docker is only watching the PID of the original command, the container then halts.

How do I prevent the container from halting? I need to be able to tell it to bind to the first child process, or stop Nginx's initial process from exiting.

Answer 1

To expand on John's answer you can also use the Dockerfile CMD command as following (in case you want it to self start without additional args)

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

Answer 2

To add Tomer and Charles answers,

Syntax to run nginx in forground in Docker container using Entrypoint:

ENTRYPOINT nginx -g 'daemon off;' 

Not directly related but to run multiple commands with Entrypoint:

ENTRYPOINT /bin/bash -x /myscripts/myscript.sh && nginx -g 'daemon off;' 

Answer 3

To expand on Charles Duffy's answer, Nginx uses the daemon off directive to run in the foreground. If it's inconvenient to put this in the configuration file, we can specify it directly on the command line. This make it easy to run in debug mode (foreground) and directly switch to running in production mode (background) by changing command line args.

To run in foreground:

nginx -g 'daemon off;'

To run in background:

nginx

Answer 4

Here you have an example of a Dockerfile that runs nginx. As mentionned by Charles, it uses the daemon off configuration:

https://github.com/darron/docker-nginx-php5/blob/master/Dockerfile#L17

Answer 5

Adding this command to Dockerfile can disable it:

RUN echo "daemon off;" >> /etc/nginx/nginx.conf

Answer 6

It is also good idea to use supervisord or runit[1] for service management.

[1] https://github.com/phusion/baseimage-docker