Connecting Django docker to remote database - django

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)")

Answer 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)