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Postgres-alpine can not connect to Django project container – CentOS

I am using CentOS 8 and GitLab ci/cd and I’m trying to deploy a Django project, I don’t have any idea why the Django container can not connect to Postgres container, you can see all of the configurations below:

Dockerfile NEW

# pull official base image
FROM python:3.9-alpine

# set environment variables
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
ENV APP_ROOT /meet-pet

# set work directory
WORKDIR ${APP_ROOT}

# install dependencies
RUN pip3 install -U pip

# install psycopg2 dependencies
RUN apk update 
    && apk add --virtual build-deps gcc python3-dev musl-dev 
    && apk add postgresql-dev gcc python3-dev musl-dev 
    && apk del build-deps 
    && apk --no-cache add musl-dev linux-headers g++ bash

COPY requirements.txt ${APP_ROOT}/requirements.txt
COPY entrypoint.sh ${APP_ROOT}/entrypoint.sh
RUN pip3 install -r ${APP_ROOT}/requirements.txt

# Set the working directory to /meet_pet
WORKDIR ${APP_ROOT}

# Copy the current directory contents into the container at /meet_pet
ADD . ${APP_ROOT}

RUN chmod 775 -R ${APP_ROOT}

ENTRYPOINT ["/meet-pet/entrypoint.sh"]

entrypoint.sh NEW

#!/bin/sh

if [ "$DATABASE" = "postgres" ]
then
    echo "Waiting for postgres..."

    while ! nc -z $POSTGRES_HOST $POSTGRES_PORT; do
      sleep 10
    done

    echo "PostgreSQL started"
fi

exec "$@"

.env

POSTGRES_DB = somthing
POSTGRES_USER = user
POSTGRES_PASSWORD = pass
POSTGRES_HOST = db
POSTGRES_PORT = 5432

.env.db

POSTGRES_DB=somthing
POSTGRES_USER=user
POSTGRES_PASSWORD=pass
POSTGRES_PORT = 5432

deploy.sh

#!/usr/bin/env bash
ssh -o StrictHostKeyChecking=no something@my_ip<< 'ENDSSH'
 cd some-thing/
 docker-compose down
 git pull https:/user:[email protected]/neo1992/something.git
 docker login -u user -p pass registry.gitlab.com
 docker pull registry.gitlab.com/neo1992/some-thing:latest
 docker-compose up -d
ENDSSH

docker-compose UPDATED

version: "3.8"

services:

  web:
    image: registry.gitlab.com/neo1992/meet-pet:latest
    build:
      context: .
    container_name: web
    command: bash -c 'python manage.py migrate --noinput && python manage.py makemigrations && python manage.py migrate --noinput && python manage.py collectstatic --noinput && gunicorn meet_pet.wsgi:application -b 0.0.0.0:8000 --capture-output --log-level=info'
    volumes:
      - static_volume:/home/meetpet/meet-pet/static
      - media_volume:/home/meetpet/meet-pet/media
    ports:
      - "8000:8000"
    depends_on:
      - db

  db:
    image: postgres:12.0-alpine
    container_name: db
    ports:
      - "5432"
    volumes:
      - postgres_data:/var/lib/postgresql/data/
    environment:
      - POSTGRES_DB=meet_pet
      - POSTGRES_USER=user
      - POSTGRES_PASSWORD=pass
      - DATABASE=postgres


  nginx:
    build: ./nginx
    container_name: nginx
    ports:
      - "80:80"
    volumes:
      - static_volume:/home/meetpet/meet-pet/static
      - media_volume:/home/meetpet/meet-pet/media
    depends_on:
      - web

volumes:
  postgres_data:
  static_volume:
  media_volume:

Django==3.1.3 DB settings:

Django setting:

from envparse import env

env.read_envfile()

DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.postgresql",
        "NAME": env("POSTGRES_DB", default=""),
        "USER": env("POSTGRES_USER", default=""),
        "PASSWORD": env("POSTGRES_PASSWORD", default=""),
        "HOST": env("POSTGRES_HOST", default=""),
        "PORT": env("POSTGRES_PORT", default=""),
    }
}

gitlab-ci.yml

image: docker:stable
services:
  - docker:dind

stages:
  - build
  - test
  - deploy

variables:
  DOCKER_HOST: tcp://docker:2375
  DOCKER_DRIVER: overlay2

before_script:
  - apk add --no-cache --update py-pip
  - pip install docker-compose~=1.23.0
  - docker login -u gitlab-ci-token -p $CI_JOB_TOKEN registry.gitlab.com

build:
  stage: build
  script:
    - docker build -t registry.gitlab.com/neo1992/some-thing .
    - docker push registry.gitlab.com/neo1992/some-thing
  only:
    - master

deploy:
  stage: deploy
  before_script:
  - apk add --no-cache openssh-client bash
  - mkdir -p ~/.ssh
  - echo "$DEPLOY_KEY" | tr -d 'r' > ~/.ssh/id_rsa
  - cat ~/.ssh/id_rsa
  - chmod 700 ~/.ssh/id_rsa
  - eval "$(ssh-agent -s)"
  - ssh-add ~/.ssh/id_rsa
  - ssh-keyscan -H 'gitlab.com' >> ~/.ssh/known_hosts
  script:
    - bash ./deploy.sh
  only:
    - master

docker network ls NEW

8d0bd4bcca7d        bridge              bridge              local
661e1139c1b8        host                host                local
8323f73cc95e        meet-pet_default    bridge              local
428d1baf38ea        none                null                local

docker meet-pet_default network inspect UPDATED

[
    {
        "Name": "meet-pet_default",
        "Id": "8323f73cc95ef0a2294b40da4ec0b20ac2a4e59a4235832f291a8601e15fad54",
        "Created": "2020-12-04T15:44:42.113742176Z",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "172.26.0.0/16",
                    "Gateway": "172.26.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": true,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "ccd43c63a88d566cda572ef1fc62d12d8ba31de485feedb3c47b96ec8fc484f4": {
                "Name": "db",
                "EndpointID": "c6598512aa0d837dd429ad0813d9206dc21ac2f6e6561c9296a1c401747e089b",
                "MacAddress": "02:42:ac:1a:00:02",
                "IPv4Address": "172.26.0.2/16",
                "IPv6Address": ""
            }
        },
        "Options": {},
        "Labels": {
            "com.docker.compose.network": "default",
            "com.docker.compose.project": "meet-pet",
            "com.docker.compose.version": "1.27.4"
        }
    }
]

docker-compose FULL logs:

ESC[33mnginx    |ESC[0m /docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
ESC[33mnginx    |ESC[0m /docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
ESC[33mnginx    |ESC[0m /docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
ESC[33mnginx    |ESC[0m 10-listen-on-ipv6-by-default.sh: /etc/nginx/conf.d/default.conf is not a file or does not exist, exiting
ESC[33mnginx    |ESC[0m /docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
ESC[33mnginx    |ESC[0m /docker-entrypoint.sh: Configuration complete; ready for start up
ESC[33mnginx    |ESC[0m 2020/12/04 09:02:28 [emerg] 1#1: host not found in upstream "meet_pet:8000" in /etc/nginx/conf.d/nginx.conf:3
ESC[33mnginx    |ESC[0m nginx: [emerg] host not found in upstream "meet_pet:8000" in /etc/nginx/conf.d/nginx.conf:3
ESC[36mdb       |ESC[0m 2020-12-04 09:02:27.279 UTC [1] LOG:  starting PostgreSQL 12.0 on x86_64-pc-linux-musl, compiled by gcc (Alpine 8.3.0) 8.
3.0, 64-bit
ESC[36mdb       |ESC[0m 2020-12-04 09:02:27.280 UTC [1] LOG:  listening on IPv4 address "0.0.0.0", port 5432
ESC[36mdb       |ESC[0m 2020-12-04 09:02:27.280 UTC [1] LOG:  listening on IPv6 address "::", port 5432
ESC[36mdb       |ESC[0m 2020-12-04 09:02:27.281 UTC [1] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
ESC[36mdb       |ESC[0m 2020-12-04 09:02:27.315 UTC [18] LOG:  database system was shut down at 2020-12-04 09:02:09 UTC
ESC[36mdb       |ESC[0m 2020-12-04 09:02:27.318 UTC [1] LOG:  database system is ready to accept connections
ESC[32mweb      |ESC[0m Traceback (most recent call last):
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/base/base.py", line 219, in ensure_connection
ESC[32mweb      |ESC[0m     self.connect()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/utils/asyncio.py", line 26, in inner
ESC[32mweb      |ESC[0m     return func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/base/base.py", line 200, in connect
ESC[32mweb      |ESC[0m     self.connection = self.get_new_connection(conn_params)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/utils/asyncio.py", line 26, in inner
ESC[32mweb      |ESC[0m     return func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/postgresql/base.py", line 187, in get_new_connection
ESC[32mweb      |ESC[0m     connection = Database.connect(**conn_params)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/psycopg2/__init__.py", line 127, in connect
ESC[32mweb      |ESC[0m     conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
ESC[32mweb      |ESC[0m psycopg2.OperationalError: could not connect to server: Host is unreachable
ESC[32mweb      |ESC[0m         Is the server running on host "db" (172.25.0.2) and accepting
ESC[32mweb      |ESC[0m         TCP/IP connections on port 5432?
ESC[32mweb      |ESC[0m 
ESC[32mweb      |ESC[0m 
ESC[32mweb      |ESC[0m The above exception was the direct cause of the following exception:
ESC[32mweb      |ESC[0m 
ESC[32mweb      |ESC[0m Traceback (most recent call last):
ESC[32mweb      |ESC[0m   File "/meet-pet/manage.py", line 22, in <module>
ESC[32mweb      |ESC[0m     main()
ESC[32mweb      |ESC[0m   File "/meet-pet/manage.py", line 18, in main
ESC[32mweb      |ESC[0m     execute_from_command_line(sys.argv)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
ESC[32mweb      |ESC[0m     utility.execute()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/core/management/__init__.py", line 395, in execute
ESC[32mweb      |ESC[0m     self.fetch_command(subcommand).run_from_argv(self.argv)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/core/management/base.py", line 330, in run_from_argv
ESC[32mweb      |ESC[0m     self.execute(*args, **cmd_options)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/core/management/base.py", line 371, in execute
ESC[32mweb      |ESC[0m     output = self.handle(*args, **options)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/core/management/base.py", line 85, in wrapped
ESC[32mweb      |ESC[0m     res = handle_func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/core/management/commands/migrate.py", line 92, in handle
ESC[32mweb      |ESC[0m     executor = MigrationExecutor(connection, self.migration_progress_callback)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/migrations/executor.py", line 18, in __init__
ESC[32mweb      |ESC[0m     self.loader = MigrationLoader(self.connection)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/migrations/loader.py", line 53, in __init__
ESC[32mweb      |ESC[0m     self.build_graph()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/migrations/loader.py", line 216, in build_graph
ESC[32mweb      |ESC[0m     self.applied_migrations = recorder.applied_migrations()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/migrations/recorder.py", line 77, in applied_migrations
ESC[32mweb      |ESC[0m     if self.has_table():
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/migrations/recorder.py", line 55, in has_table
ESC[32mweb      |ESC[0m     with self.connection.cursor() as cursor:
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/utils/asyncio.py", line 26, in inner
ESC[32mweb      |ESC[0m     return func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/base/base.py", line 219, in ensure_connection
ESC[32mweb      |ESC[0m     self.connect()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/utils.py", line 90, in __exit__
ESC[32mweb      |ESC[0m     raise dj_exc_value.with_traceback(traceback) from exc_value
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/base/base.py", line 219, in ensure_connection
ESC[32mweb      |ESC[0m     self.connect()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/utils/asyncio.py", line 26, in inner
ESC[32mweb      |ESC[0m     return func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/base/base.py", line 200, in connect
ESC[32mweb      |ESC[0m     self.connection = self.get_new_connection(conn_params)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/utils/asyncio.py", line 26, in inner
ESC[32mweb      |ESC[0m     return func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/postgresql/base.py", line 187, in get_new_connection
ESC[32mweb      |ESC[0m     connection = Database.connect(**conn_params)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/psycopg2/__init__.py", line 127, in connect
ESC[32mweb      |ESC[0m     conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
ESC[32mweb      |ESC[0m django.db.utils.OperationalError: could not connect to server: Host is unreachable
ESC[32mweb      |ESC[0m         Is the server running on host "db" (172.25.0.2) and accepting
ESC[32mweb      |ESC[0m         TCP/IP connections on port 5432?
ESC[32mweb      |ESC[0m 
ESC[32mweb      |ESC[0m Traceback (most recent call last):
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/base/base.py", line 219, in ensure_connection
ESC[32mweb      |ESC[0m     self.connect()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/utils/asyncio.py", line 26, in inner
ESC[32mweb      |ESC[0m     return func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/base/base.py", line 200, in connect
ESC[32mweb      |ESC[0m     self.connection = self.get_new_connection(conn_params)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/utils/asyncio.py", line 26, in inner
ESC[32mweb      |ESC[0m     return func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/postgresql/base.py", line 187, in get_new_connection
ESC[32mweb      |ESC[0m     connection = Database.connect(**conn_params)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/psycopg2/__init__.py", line 127, in connect
ESC[32mweb      |ESC[0m     conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
ESC[32mweb      |ESC[0m psycopg2.OperationalError: could not connect to server: Host is unreachable
ESC[32mweb      |ESC[0m         Is the server running on host "db" (172.25.0.2) and accepting
ESC[32mweb      |ESC[0m         TCP/IP connections on port 5432?
ESC[32mweb      |ESC[0m 
ESC[32mweb      |ESC[0m 
ESC[32mweb      |ESC[0m The above exception was the direct cause of the following exception:
ESC[32mweb      |ESC[0m 
ESC[32mweb      |ESC[0m Traceback (most recent call last):
ESC[32mweb      |ESC[0m   File "/meet-pet/manage.py", line 22, in <module>
ESC[32mweb      |ESC[0m     main()
ESC[32mweb      |ESC[0m   File "/meet-pet/manage.py", line 18, in main
ESC[32mweb      |ESC[0m     execute_from_command_line(sys.argv)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
ESC[32mweb      |ESC[0m     utility.execute()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/core/management/__init__.py", line 395, in execute
ESC[32mweb      |ESC[0m     self.fetch_command(subcommand).run_from_argv(self.argv)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/core/management/base.py", line 330, in run_from_argv
ESC[32mweb      |ESC[0m     self.execute(*args, **cmd_options)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/core/management/base.py", line 371, in execute
ESC[32mweb      |ESC[0m     output = self.handle(*args, **options)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/core/management/base.py", line 85, in wrapped
ESC[32mweb      |ESC[0m     res = handle_func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/core/management/commands/migrate.py", line 92, in handle
ESC[32mweb      |ESC[0m     executor = MigrationExecutor(connection, self.migration_progress_callback)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/migrations/executor.py", line 18, in __init__
ESC[32mweb      |ESC[0m     self.loader = MigrationLoader(self.connection)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/migrations/loader.py", line 53, in __init__
ESC[32mweb      |ESC[0m     self.build_graph()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/migrations/loader.py", line 216, in build_graph
ESC[32mweb      |ESC[0m     self.applied_migrations = recorder.applied_migrations()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/migrations/recorder.py", line 77, in applied_migrations
ESC[32mweb      |ESC[0m     if self.has_table():
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/migrations/recorder.py", line 55, in has_table
ESC[32mweb      |ESC[0m     with self.connection.cursor() as cursor:
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/utils/asyncio.py", line 26, in inner
ESC[32mweb      |ESC[0m     return func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/base/base.py", line 259, in cursor
ESC[32mweb      |ESC[0m     return self._cursor()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/base/base.py", line 235, in _cursor
ESC[32mweb      |ESC[0m     self.ensure_connection()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/utils/asyncio.py", line 26, in inner
ESC[32mweb      |ESC[0m     return func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/base/base.py", line 219, in ensure_connection
ESC[32mweb      |ESC[0m     self.connect()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/utils.py", line 90, in __exit__
ESC[32mweb      |ESC[0m     raise dj_exc_value.with_traceback(traceback) from exc_value
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/base/base.py", line 219, in ensure_connection
ESC[32mweb      |ESC[0m     self.connect()
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/utils/asyncio.py", line 26, in inner
ESC[32mweb      |ESC[0m     return func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/base/base.py", line 200, in connect
ESC[32mweb      |ESC[0m     self.connection = self.get_new_connection(conn_params)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/utils/asyncio.py", line 26, in inner
ESC[32mweb      |ESC[0m     return func(*args, **kwargs)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/django/db/backends/postgresql/base.py", line 187, in get_new_connection
ESC[32mweb      |ESC[0m     connection = Database.connect(**conn_params)
ESC[32mweb      |ESC[0m   File "/usr/local/lib/python3.9/site-packages/psycopg2/__init__.py", line 127, in connect
ESC[32mweb      |ESC[0m     conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
ESC[32mweb      |ESC[0m django.db.utils.OperationalError: could not connect to server: Host is unreachable
ESC[32mweb      |ESC[0m         Is the server running on host "db" (172.25.0.2) and accepting
ESC[32mweb      |ESC[0m         TCP/IP connections on port 5432?
ESC[32mweb      |ESC[0m

I’ve checked every solution that I could found, but none of them works and I still have this error.

Tags:

2

Answers


  1. Chosen as BEST ANSWER
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    The problem is not with docker-compose, It's because of the firewall. CentOS firewall blocked 5432 port.

    to open 5432 port permanently use the below commands:

    sudo firewall-cmd --zone=public --add-masquerade --permanent
sudo firewall-cmd --permanent --zone=public --change-interface=docker0
sudo firewall-cmd --permanent --direct --add-rule ipv4 filter INPUT 4 -i docker0 -j ACCEPT
sudo firewall-cmd --permanent --zone=public --add-port=[YOURPORT]/tcp

    Notice: swap out "[YOURPORT]" for the actual port.. i.e. 5432 and swap out the "docker0" network if you've named it something else.

    for checking network list use: docker network ls and you can see all networks.


  2. 0

    Postgres needs about ten or so seconds to initialize an empty database. Don’t be fooled by this fancy depends_on property: it only waits for the mentioned container(s) to start. It doesn’t care if it’s ready. Docker documentation says about it that you have to create an application that can tolerate missing components instead of relying on depends_on.

    While you didn’t make one, you can add restart: on-failure property to your service definition in the compose file. With it Docker will restart the container if it fails. You can also add some simple check that the database is at least listening: while !</dev/tcp/db/5432; do sleep 3; done;. Add this before python manage.py and it will run a loop checking if db is listening on 5432 and sleeping if it’s not.

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