store-data-with-volumes.md

Store Data With Volumes

Category: Docker

Volumes are the preferred way to persist data in Docker containers and services as they allow you to back up, restore, or migrate data from one Docker host to another.

The approach outlined here creates a volume which is used in a Swarm deployment.

Create the volume

docker volume create my-vol

Inspect the volume

docker volume inspect my-vol

[
    {
        "CreatedAt": "2020-11-01T02:55:54Z",
        "Driver": "local",
        "Labels": {},
        "Mountpoint": "/var/lib/docker/volumes/my-vol/_data",
        "Name": "my-vol",
        "Options": {},
        "Scope": "local"
    }
]

Reference the volume in a compose file

version: "3.8"
services:

  data-lake:
    image: data-lake-service:latest
    ports:
      - "8080:8080"    
    volumes:
      - my-vol:/opt/app/etl

volumes:
  my-vol:
    external: true

Backup data in a volume

To back up the volume’s directory (such as /var/lib/docker/volumes/my-vol), stop the container that is using the volume and copy the directory contents to another location.

Remove a volume

docker volume rm my-vol

See Using data volumes in Docker for more details.