How to Modify docker-compose.yml for Easy Backup and Restore#

What is docker-compose.yml?#

Think of docker-compose.yml as a recipe. You list all the ingredients you need, and Docker gathers everything and sets it up automatically. The example below has an app and a database that need to work together.

services:
  app:
    image: example.com/app:latest
    ports:
      - "80:80"
    environment:
      USERNAME: ****
      PASSWORD: ****
    depends_on:
      - db
  
  db:
    image: postgres:16
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: postgres
      POSTGRES_DB: postgres
    volumes:
      - postgres_data:/var/lib/postgresql/data

  volumes:
    postgres_data:

Bind mounts#

By default, Docker stores data in a hidden directory on your computer (/var/lib/docker/volumes). Instead, you can store your data in a folder next to the docker-compose.yml file.

1. Comment out the top-level volumes section:

# volumes:
#   postgres_data:

2. Update the database volume section to use ./:

db:
  volumes:
    - ./postgres_data:/var/lib/postgresql/data

The ./ tells Docker to store data locally in your project folder, not in the hidden system directory.

3. To backup, just copy your project folder. To restore, paste the folder back and run docker compose up -d

Pin Your Image Versions#

app:
  image: example.com/app:latest

The part after the colon (:) specifies which version of the image Docker should pull. A Docker image contains everything your app needs, such as the code and configuration. Think of it as a snapshot.

The latest tag downloads whatever the current version is, and that’s risky. Your app might break after a major update.

This happened to me with Lychee. When I restored it on a new VPS, Docker automatically pulled the newest version that wasn’t compatible with my backup. The app broke.

Avoid latest. Instead, visit Docker Hub, search for your app, and use the most recent version tag:

app:
  image: example.com/app:v1.0.0

Organize Multiple Docker Applications for Easy Backups#

1. Create a docker folder: mkdir docker; cd docker

2. Inside the docker folder, create app folders. mkdir app1 app2 app3

3. In each app folder, create docker-compose.yml.

docker/
  app1/
    docker-compose.yml
  app2/
    docker-compose.yml
  app3/
    docker-compose.yml

4. When you backup, just backup the docker folder: tar -cvf docker.tar docker/. When you restore, just paste the docker folder back.