Issues with Volume in Docker - Compose Fail to install Django App.

June 30, 2016 5.4k views
Docker Django Deployment
vinitpatankar
By:
vinitpatankar

I am trying to install an application from github to my droplet and the Docker-compose.yml file includes mapping volumes.

The github location for the app is www.github.com/18f/tock which has the following instruction to set up the up using the docker console.

$ cp .env.sample .env
$ docker-compose build
$ docker-compose run app python manage.py migrate
$ docker-compose run app python manage.py loaddata test_data/data-update.json

The thing works perfectly on the local machine and I was able to get it working in the local docker installation.
Here is a link I am using to https://realpython.com/blog/python/django-development-with-docker-compose-and-machine/

app:
build: .
volumes:
- ./tock:/tock
links:
- db
working_dir: /tock
entrypoint: python /tock/docker_entrypoint.py
environment:
- PYTHONUNBUFFERED=yup
- DATABASE_URL=postgres://tock_user@db/tock
- RUNNING_IN_DOCKER=yup
- DJANGO_SETTINGS_MODULE=tock.settings.dev
command: "python manage.py runserver 0.0.0.0:${EXTERNAL_PORT}"

However when I run the docker-compose run app python manage.py migrate statement, it says that the /tock/docker_entrypoint.py file not found. 

python: can't open file '/tock/docker_entrypoint.py': [Errno 2] No such file or directory

Google results indicate that the mount of the volume is not working and I am trying to find out how to confirm that the volume is being mounted.

On running docker volume ls I am seeing a bunch of volumes but the names are not consistent.

Also when I look at the volumes section I see that the Name of the volume is not tock but some random guid.

docker volume inspect e32d8cdf9a61015bc4230781878c715ef56cf6c47536e17c75721c6a47455204
[
    {
        "Name": "e32d8cdf9a61015bc4230781878c715ef56cf6c47536e17c75721c6a47455204",
        "Driver": "local",
        "Mountpoint": "/var/lib/docker/volumes/e32d8cdf9a61015bc4230781878c715ef56cf6c47536e17c75721c6a47455204/_data",
        "Labels": null
    }
]

I am a newbie and have been trying to get this working but with no luck as the mount does not work.

4 comments
  • gndo July 1, 2016

    What’s in the Dockerfile? You specified a build in your docker-compose.yml file but did not display the Dockerfile.

  • vinitpatankar July 1, 2016 
    FROM python:3.4

RUN apt-get update && \
  apt-get install -y ruby-full rubygems && \
  gem install sass

COPY requirements.txt requirements-dev.txt /tock/

RUN pip install -r /tock/requirements.txt -r /tock/requirements-dev.txt
  • gndo July 1, 2016

    @vinitpatankar - I believe the image is using the default CMD, which is to run docker_entrypoint.py in the current WORKDIR. To test this, add this to the end of your Dockerfile:

    # Override test of default command to port 9876
CMD  ["python", "manage.py", "runserver", "0.0.0.0:9876"]

    The error message you’re seeing now should go away, though you may get a new message once it runs.

  • vinitpatankar July 1, 2016

    I will try that but then there is an explicit call to the docker entry point in docker_compose.yml file. Is this something that is not related?

     entrypoint: python /tock/docker_entrypoint.py
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1 Answer
ryanpq MOD July 27, 2016

This question was answered by @gndo:

@vinitpatankar - I believe the image is using the default CMD, which is to run docker_entrypoint.py in the current WORKDIR. To test this, add this to the end of your Dockerfile:

# Override test of default command to port 9876
CMD  ["python", "manage.py", "runserver", "0.0.0.0:9876"]

The error message you’re seeing now should go away, though you may get a new message once it runs.

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  • emoffett November 5, 2017

    I found this answer helpful as it highlighted to me that each part of the command needed to be separated; i.e. my command with fewer quotes and commas, to the effect of CMD [“python”, “manage.py runserver 0.0.0.0:9876”], did not work and docker couldn’t find the improbably named file “manage.py runserver 0.0.0.0:9876”. Until twigging while reading this ryanpq’s answer, I spent quite a lot of time trying to solve why docker couldn’t find the file “manage.py”.

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