Docker Compose Volumes

Docker Compose Volumes provide a way to persist data across containers and services.

Introduction

Docker Compose Volumes allow you to share data between containers and services by creating a shared filesystem that can be accessed by multiple containers. This allows you to store and persist data even if a container is removed or restarted.

Creating a Volume

To create a Docker Compose Volume, you can simply add the volumes key to your docker-compose.yml file:

version: '3'
services:
  web:
    image: nginx:latest
    volumes:
      - my-volume:/usr/share/nginx/html
volumes:
  my-volume:

In this example, we create a volume called my-volume and mount it as a directory inside the web container.

Sharing a Volume

Once a volume is created, it can be shared between multiple services. To do this, simply reference the same volume in the volumes key of each service:

version: '3'
services:
  db:
    image: postgres:latest
    volumes:
      - my-volume:/var/lib/postgresql/data
  web:
    image: nginx:latest
    volumes:
      - my-volume:/usr/share/nginx/html
volumes:
  my-volume:

In this example, we create a volume called my-volume and share it between a db service running Postgres and a web service running Nginx.

Persisting Data

Docker Compose Volumes allow you to persist data even if a container is removed or restarted. This can be achieved by using a named volume, as shown in the above examples.

Named volumes are stored in a location on the host filesystem and are not deleted when a container is removed. This makes them ideal for persisting data that should survive container restarts, such as database data.

Conclusion

Docker Compose Volumes provide a way to share data between containers and services, and to persist data even if a container is removed or restarted. They are an essential tool for building complex containerized applications, and are easy to use and configure.