Launching gunicorn instances a docker image, using docker run

Question

In my dockerfile, for a Flask app, I have a set of commands that work as planned. The last line of my dockerfile is currently:

ENTRYPOINT [ "/bin/bash", "-c" ]

I need to launch some gunicorn instances for this image. So, I run the following commands in the terminal, outside the image.

$ docker run -itd --name running_name -p 5000:5000 image_name bash

If I run without bash, I'll just enter exit the container automatically after a few seconds...

$docker container exec -it running_name  /bin/bash -c bash

Now that I'm in, I launch the gunicorn instances, and do docker exit. Because of exec, the instances are still running.

Is there a way to launch the gunicorn instances from docker run, without having to enter into the container?

I've tried ENTRYPOINT [ "gunicorn", "--bind", "0.0.0.0:5000" ] but I still exit automatically

I've also tried substituting the last line for CMD gunicorn --bind 0.0.0.0:5000 and then do docker run -d --name run_name -p 5000:5000 image_name

I still exit automatically.

Edit: To reflect the possible answer below, here's my updated tries and extra information.

The following files are all at the same level of the directory structure.

In the api_docker.py file, I have:

app = Flask(__name__)
api = Api(app)
api.add_resource(<some_code>)

In the gunicorn.conf.py file, I have:

worker_class = "gevent"
workers = 2
timeout = 90
bind = "0.0.0.0:5000"
wsgi_app = "wsgi:app"
errorlog = "logging/error.log"
capture_output = True
loglevel = "debug"
daemon = True
enable_stdio_inheritance = True
preload = True

I've also tried removing the bind and wsgi_app rows, from this file.

In the dockerfile:

<some_code>
CMD ["gunicorn", "--conf", "gunicorn.conf.py", "--bind", "0.0.0.0:5000", "api_docker:app"]

I build successfully, and then I do:

docker run -d --name name_run -p 5000:5000 name_image

Answer 1

To solve this issue, I did the following:

1. Removed the options daemon , enable_stdio_inheritance, and preload from the conf file.
2. I also increased the timeout and graceful timeout parameters to 120.
3. Gunicorn will look for a conf file, and will use the parameter values defined therein, unless they are overwritten in th CLI. Therefore, I just ran CMD ["gunicorn"].

I think the most important change was that of point 1, namely the daemon to false(which is the default), not sure why though... I would guess that as a daemon process, the docker container would not monitor it correctly and just exit.