Can't connect postgresql in a docker (receiving fastshut down request) - django

Question

I am running a django/postgresql in docker container. When run docker-compose.yml, the postgresql service will start and listen for a moment then it will be shut-down with LOG:
"listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432" then
"database system was shut down".
I have read it somewhere that it is receiving a postmaster fast shutdown request but I don't know how to solve this. I have tried to change ports and other PostgreSQL env variables without success.
Here is my .ylm for docker-compose
version: '3'
volumes:
postgres_data_local: {}
postgres_backup_local: {}
services:
django:
build:
context: .
dockerfile: ./compose/local/django/Dockerfile
depends_on:
- postgres
- redis
volumes:
- .:/app
env_file: .env
ports:
- "8000:8000"
command: /start.sh
postgres:
image: postgres:10.1-alpine
build:
context: .
dockerfile: ./compose/production/postgres/Dockerfile
volumes:
- postgres_data_local:/var/lib/postgresql/data
- postgres_backup_local:/backups
env_file: .env
redis:
image: redis:3.0
ports:
- '6379:6379'
My .env file is somehow like
# PostgreSQL conf
POSTGRES_PASSWORD=p3wrd
POSTGRES_USER=postgres
POSTGRES_DB=postgres
POSTGRES_HOST=127.0.0.1 #have tried localhost, 0.0.0.0 etc
POSTGRES_PORT=5432
DATABASE_URL= postgresql://postgres:p3wrd#127.0.0.1:5432/postgres
# General settings
READ_DOT_ENV_FILE=True
SETTINGS_MODULE=config.settings.test
SECRET_KEY=Sup3rS3cr3tP#22word
DEBUG=True
ALLOWED_HOSTS=*
# URL for Redis
REDIS_URL=redis://127.0.0.1:6379

Answer 1

Why are you setting POSTGRES_HOST to 127.0.0.1 or variants thereof? That means "localhost", which in a container means "the local container". Postgres isn't running inside the django container so that won't work.
Since you're using docker-compose, your containers are all running in a user-defined network. This means that Docker maintains a DNS server for you that maps service names to container ip addresses. In other words, you can simply set:
POSTGRES_HOST=postgres
DATABASE_URL= postgresql://postgres:p3wrd#postgres:5432/postgres