How to create a persistent data volume for Postgres Database container within a Docker project?

December 15, 2018 10.9k views
Docker Databases PostgreSQL Django DigitalOcean Ubuntu 18.04

I have a docker project running in a droplet with a Postgres Container. As the container is ephemeral and can disappear when the droplet goes away, I want to attach a persistent volume so the database is separate from the droplet. Is this the right way to go about this? I have looked for a tutorial but I can’t seem to find it.

What is the right way to approach a persistent database(like RDS on AWS) that is separate from the droplet?

The project is running Django, Caddy, and Postgres.

1 Answer

Use a volume.

My docker-compose.yml:

version: '3.1'

services:
 db:
  image: postgres
  restart: always
  environment:
   POSTGRES_PASSWORD: mypassword
  volumes:
    - ./postgres-data:/var/lib/postgresql/data
  ports:
    - 5432:5432

the local postgres-data/ directory will now be used by the postgres container.

mount your volume to your droplet

make a symbolic link to your volume mount:

ln -s /mnt/<volume_name> ./postgres-data

Start the postgres server:

docker-compose up -d 

when you stop or down the docker container, the database will still be there. You can even destroy the droplet, you’ll still have your database on your volume.

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