Connecting Django docker to remote database

Question

I have a Django application running on docker connected to a database in another container on the same host. This seams to work fine, but when I try to change the connection to a database on another server, it fails to connect. Not only that, but when I try to connect to the Django application in the browser(like admin or api) I get no response, and see no activity in the output log. The application runs fine with the remote database if I run it outside the container, and the database is set to accept all IPs for the user I am trying to connect with.

Any Ideas as to why I am not getting a connection?

Dockerfile:

FROM python:3.8-alpine

ENV PATH="/scripts:${PATH}"

COPY ./requirements.txt /requirements.txt
RUN apk add --update --no-cache --virtual .tmp gcc libc-dev linux-headers
RUN apk add mariadb-dev python3-dev postgresql-dev
RUN pip install -r /requirements.txt
RUN apk del .tmp

RUN mkdir /app_django
COPY ./app_django /app_django
WORKDIR /app_django
COPY ./scripts /scripts

RUN chmod +x /scripts/*

RUN mkdir -p /vol/web/media
RUN mkdir -p /vol/web/static
RUN adduser -D user
RUN chown -R user:user /vol
RUN chmod -R 755 /vol/web
USER user

CMD ["entrypoint.sh"]

docker-compose.yml

version: '3.7'

services:
  db:
    build: mysql/
    environment:
      MYSQL_ROOT_PASSWORD: 'password'
      MYSQL_DATABASE: database
    volumes:
      - ./mysql/data:/var/lib/mysql
      - ./mysql/conf:/etc/mysql/conf.d
      - ./mysql/entrypoint-initdb.d:/docker-entrypoint-initdb.d/
      - ./mysql/backup_database:/var/local/mysql/backups
    ports:
      - 3306:3306
    restart: always
    
  pdb:
    build:
      context: .
    ports:
      - "8000:8000"
    volumes:
      - ./pdb_django:/pdb_django
    command: sh -c "python manage.py runserver 0.0.0.0:8000"
    environment:
      - DEBUG=1

entrypoint.sh

#!/bin/sh

set -e

python manage.py collectstatic --noinput

uwsgi --socket :8000 --master --enable-threads --module app.wsgi

Django db settings (the commented parts is used when conection to db on host container):

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'database',
        'HOST': '<remote IP>',
        # 'HOST': 'db',
        'USER': 'user',
        'PASSWORD': 'password',
        'PORT': '3308'
        # 'PORT': '3306',
    }
}

requirements.txt

Django==3.1.4
uWSGI>=2.0.18,<2.1
django-filter==2.4.0
djangorestframework==3.12.2
mysql-connector-python==8.0.22
mysqlclient==2.0.2
PyMySQL==0.10.1
sqlparse==0.4.1

Outputlog for application:

pdb_1  | Watching for file changes with StatReloader
pdb_1  | Exception in thread django-main-thread:
pdb_1  | Traceback (most recent call last):
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 219, in ensure_connection
pdb_1  |     self.connect()
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
pdb_1  |     return func(*args, **kwargs)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 200, in connect
pdb_1  |     self.connection = self.get_new_connection(conn_params)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
pdb_1  |     return func(*args, **kwargs)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/mysql/base.py", line 234, in get_new_connection
pdb_1  |     return Database.connect(**conn_params)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/MySQLdb/__init__.py", line 130, in Connect
pdb_1  |     return Connection(*args, **kwargs)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/MySQLdb/connections.py", line 185, in __init__
pdb_1  |     super().__init__(*args, **kwargs2)
pdb_1  | MySQLdb._exceptions.OperationalError: (2002, "Can't connect to MySQL server on '<remote IP>' (115)")
pdb_1  |
pdb_1  | The above exception was the direct cause of the following exception:
pdb_1  |
pdb_1  | Traceback (most recent call last):
pdb_1  |   File "/usr/local/lib/python3.8/threading.py", line 932, in _bootstrap_inner
pdb_1  |     self.run()
pdb_1  |   File "/usr/local/lib/python3.8/threading.py", line 870, in run
pdb_1  |     self._target(*self._args, **self._kwargs)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/utils/autoreload.py", line 53, in wrapper
pdb_1  |     fn(*args, **kwargs)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/core/management/commands/runserver.py", line 121, in inner_run
pdb_1  |     self.check_migrations()
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/core/management/base.py", line 459, in check_migrations
pdb_1  |     executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/migrations/executor.py", line 18, in __init__
pdb_1  |     self.loader = MigrationLoader(self.connection)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/migrations/loader.py", line 53, in __init__
pdb_1  |     self.build_graph()
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/migrations/loader.py", line 216, in build_graph
pdb_1  |     self.applied_migrations = recorder.applied_migrations()
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/migrations/recorder.py", line 77, in applied_migrations
pdb_1  |     if self.has_table():
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/migrations/recorder.py", line 55, in has_table
pdb_1  |     with self.connection.cursor() as cursor:
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
pdb_1  |     return func(*args, **kwargs)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 259, in cursor
pdb_1  |     return self._cursor()
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 235, in _cursor
pdb_1  |     self.ensure_connection()
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
pdb_1  |     return func(*args, **kwargs)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 219, in ensure_connection
pdb_1  |     self.connect()
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/utils.py", line 90, in __exit__
pdb_1  |     raise dj_exc_value.with_traceback(traceback) from exc_value
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 219, in ensure_connection
pdb_1  |     self.connect()
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
pdb_1  |     return func(*args, **kwargs)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 200, in connect
pdb_1  |     self.connection = self.get_new_connection(conn_params)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
pdb_1  |     return func(*args, **kwargs)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/mysql/base.py", line 234, in get_new_connection
pdb_1  |     return Database.connect(**conn_params)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/MySQLdb/__init__.py", line 130, in Connect
pdb_1  |     return Connection(*args, **kwargs)
pdb_1  |   File "/usr/local/lib/python3.8/site-packages/MySQLdb/connections.py", line 185, in __init__
pdb_1  |     super().__init__(*args, **kwargs2)
pdb_1  | django.db.utils.OperationalError: (2002, "Can't connect to MySQL server on '<remote IP>' (115)")

The application is trying to connect to '' which is not a valid ip. set the correct ip in Django db settings — Igor Moraru, Dec 17 '20 at 11:59
@IgorMoraru Hi, I changed it to before posting for security reasons, in the original code its a valid IP — Kasper Skjeggestad, Dec 17 '20 at 12:04
Have you changed the port on which mysql is running on remote, because in your setting it is 3308, but the default is 3306 — Igor Moraru, Dec 17 '20 at 12:09
@IgorMoraru Yes, the remote database is actually also in a docker container. The server has multiple database containers. This is a test database, so it is set to a different port then default — Kasper Skjeggestad, Dec 17 '20 at 12:23
No clue. Check if this solution works for you: https://stackoverflow.com/questions/58547120/django-db-utils-operationalerror-2002-cant-connect-to-mysql-server-on-db — Igor Moraru, Dec 17 '20 at 15:06

score 1 · Answer 1 · answered Dec 18 '20 at 09:04

1

It would seem this was an issue with my VPN. When I tried to run the container on a server on the network it worked fine, and I was also able to get responses when I turned off my VPN (although I could obviously not access the database on the server)

answered Dec 18 '20 at 09:04

Kasper Skjeggestad

135
1
11

Connecting Django docker to remote database

1 Answers1