How to keep Docker container running after starting services?

I've seen a bunch of tutorials that seem do the same thing I'm trying to do, but for some reason my Docker containers exit. Basically, I'm setting up a web-server and a few daemons inside a Docker container. I do the final parts of this through a bash script called run-all.sh that I run through CMD in my Dockerfile. run-all.sh looks like this:

service supervisor start
service nginx start

And I start it inside of my Dockerfile as follows:

CMD ["sh", "/root/credentialize_and_run.sh"]

I can see that the services all start up correctly when I run things manually (i.e. getting on to the image with -i -t /bin/bash), and everything looks like it runs correctly when I run the image, but it exits once it finishes starting up my processes. I'd like the processes to run indefinitely, and as far as I understand, the container has to keep running for this to happen. Nevertheless, when I run docker ps -a, I see:

➜  docker_test  docker ps -a
CONTAINER ID        IMAGE                            COMMAND                CREATED             STATUS                      PORTS               NAMES
c7706edc4189        some_name/some_repo:blah   "sh /root/run-all.sh   8 minutes ago       Exited (0) 8 minutes ago                        grave_jones

What gives? Why is it exiting? I know I could just put a while loop at the end of my bash script to keep it up, but what's the right way to keep it from exiting?

If you are using a Dockerfile, try:

ENTRYPOINT ["tail", "-f", "/dev/null"]

(Obviously this is for dev purposes only, you shouldn't need to keep a container alive unless it's running a process eg. nginx...)

I just had the same problem and I found out that if you are running your container with the -t and -d flag, it keeps running.

docker run -td <image>

Here is what the flags do (according to docker run --help):

-d, --detach=false         Run container in background and print container ID
-t, --tty=false            Allocate a pseudo-TTY

The most important one is the -t flag. -d just lets you run the container in the background.

This is not really how you should design your Docker containers.

When designing a Docker container, you're supposed to build it such that there is only one process running (i.e. you should have one container for Nginx, and one for supervisord or the app it's running); additionally, that process should run in the foreground.

The container will "exit" when the process itself exits (in your case, that process is your bash script).

However, if you really need (or want) to run multiple service in your Docker container, consider starting from "Docker Base Image", which uses runit as a pseudo-init process (runit will stay online while Nginx and Supervisor run), which will stay in the foreground while your other processes do their thing.

They have substantial docs, so you should be able to achieve what you're trying to do reasonably easily.