How to backup, rename and restore volume with Docker

Question

In docker compose I use volumes_from to load database container data from another container.

  mssql-server-linux:
    image: mssql-server-linux:2017-latest
    depends_on:
      - mssql-server-linux-data
    volumes_from:
      - mssql-server-linux-data

  mssql-server-linux-data:
    image: mssql-server-linux-data-keva:latest
    entrypoint: /bin/sh
    volumes:
      - /var/opt/mssql

As a result, the database container uses the following volume to store it's data

$ docker volume ls
DRIVER    VOLUME NAME
local     e0368e9ae230de6578bb18a3a70823d93ecc4acab7905f96380aff4689024c25

I would like to backup and restore database changes with new named image and volume. How do I do this?

EDIT

I tried to back up the volume in tar with no luck either

$ docker run --rm --volumes-from emma_mssql-server-linux_1 -v /c/temp:/backup ubuntu tar cvf /backup/backup.tar /var/opt/mssql
tar: Cannot connect to C: resolve failed

Answer 1

I am not sure this is the root cause for your failure - but have you tried to perform the rename and backup in separate steps?

1. Remove the old volume

   docker volume rm <old-volume-name>

2. Create a new volume with the name you want to have

   docker volume create --name <new-volume-name>

3. Backup the newly created volume

   docker run --rm --volumes-from <container-name> -v $(pwd):/backup busybox tar cvf /backup/<volume-name>.tar /<volume-path>

please share if this resolves it for you.

Please Note: the assumption is that the volume is local on your system - otherwise, it might be a permissions issue and in that case, you may want to create a local copy of the volume before you back it up:

docker cp <container-name>:/<volume-path>/<volume-name>.tar <local-directory>