How can I run a Docker container on a remote server in the same manner as docker-compose up?

Question

TL;DR: Getting error /docker-entrypoint.sh: line 10: exec: nginx: cannot execute: Is a directory running docker run username/srdc_prod:2020.07.26 when docker-compose up works just fine.

I have a docker container that I have pushed to DockerHub. I am able to run this locally with docker-compose up. I pulled this down on my remote server and now I am trying to use docker run username/srdc_prod:2020.07.26.

When I do this I get the error /docker-entrypoint.sh: line 10: exec: nginx: cannot execute: Is a directory. Executing docker-compose up works just fine locally. I want to push this image to Docker Hub and pull this down and run it on my remote server. However, I cannot use docker-compose up because the docker-compose.yaml file does not exist remotely. I realize I could try cloning my GitHub repo remotely and then run docker-compose up but this defeats the purpose of pushing the container to DockerHub and eventually getting CI/CD set up.

Is there a way to run docker-compose up on a container? Or is it possible to see all of the commands executed? I saw in this question that I can use docker ps --no-trunc to see all of the commands executed for running docker containers, but all of these rely on the docker-entrypoint.sh file with which I cannot seem to execute remotely. Am I doing this all wrong and I need to refactor my Dockerfile to run on the remote server?

Image on Remote Server

username@ubuntu-512mb-name:~$ docker image ls
WARNING: Error loading config file: /home/username/.docker/config.json: stat /home/username/.docker/config.json: permission denied
REPOSITORY                TAG                 IMAGE ID            CREATED             SIZE
username/srdc_prod        2020.07.26          af62927882ee        5 days ago          504MB

docker-entrypoint.sh

  1 #!/bin/bash
  2
  3 echo "Collect static files"
  4 python manage.py collectstatic --noinput
  5
  6 echo "Apply database migrations"
  7 python manage.py migrate --noinput
  8
  9 echo "Starting daphne server"
 10 exec "$@" # offending line

Dockerfile

FROM python:3-alpine

# set env vars
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1

RUN mkdir /app

RUN apk update && apk add --no-cache postgresql-dev gcc libffi-dev musl-dev build-base python3-dev bash

COPY requirements.txt /app/requirements.txt
RUN pip install --upgrade pip && pip install --no-cache-dir -r /app/requirements.txt

COPY test-requirements.txt /app/test-requirements.txt
RUN pip install --upgrade pip && pip install --no-cache-dir -r /app/test-requirements.txt

COPY . /app
# set working directory
WORKDIR /app

RUN mkdir -p /var/www/srdc/static/
RUN chmod 755 /var/www/srdc/static/

EXPOSE 8000

ENV DJANGO_SETTINGS_MODULE=srdc.settings

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

ADD docker-entrypoint.sh /docker-entrypoint.sh
RUN chmod a+x /docker-entrypoint.sh
ENTRYPOINT ["/docker-entrypoint.sh"]

docker-compose.yml

version: '3'

services:
  django_web:
    build: .
    command: bash -c "daphne -b 0.0.0.0 -p 8000 srdc.asgi:application"
    expose:
       - 8000
    image: srdc:v0
    container_name: srdc_django_web
    volumes:
      - .:/app
      - static_volume:/var/www/srdc/static/
    depends_on:
      - db
  nginx:
    build: ./nginx
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - static_volume:/var/www/srdc/static/
      - ./data/certbot/conf:/etc/letsencrypt
      - ./data/certbot/www:/var/www/certbot
    depends_on:
      - django_web
  db:
    image: postgres
    container_name: "my_postgres"
    ports:
      - "54320:5432"
    volumes:                                                                                                                                                                                     - my_dbdata:/var/lib/postgresql/data
volumes:                                                                                                                                                                                       my_dbdata:
    static_volume:                                                                                                                                                                             media_volume:

Answer 1

The error you're seeing is accurate: nginx is a directory. Based on your docker-compose.yml manifset, there is an nginx folder in your root directory which you use as a build context for your nginx service.

  nginx:
    build: ./nginx # Here's the evidence for the nginx folder.
    ports:

When you build the django_web image, you copy over the entire context directory into /app, and that includes the nginx directory.

COPY . /app
# set working directory
WORKDIR /app

The CMD for your username/srdc_prod image is nginx -g daemon off;, which your docker-entrypoint.sh executes. That fails because nginx is a directory.

Based on your docker-compose.yml manifest, it looks like the CMD you actually want is daphne -b 0.0.0.0 -p 8000 srdc.asgi:application or something like that, but not nginx which is not installed in that alpine-based image.

Some recommendations outside of the scope of the question.

1. If you're using docker-compose in dev, consider using that in your hosted environments, too, instead of running the raw docker run commands.
2. Better yet, use Docker in swarm mode. You can re-use your manifest file that way, albeit you would need to remove some of the deprecated stuff (depends_on, for example) and expand on the service definitions a bit. Using swarm mode--or some other orchestration tool--will make it easier to scale your service in the future, plus you get some other handy features like secrets, restart policies, network segregation, and so on.