The bristle.io team has created a container to do docker volume backups

docker run \
  --rm \
  -v application_config:/src \
  -v application_backup:/dest \
  bristleio/backup

The parameters that are used to facilitate the backup are the volumes that attach to /src and /dest. /src will always copy to /dest but it will not remove items on /dest. The volume attached to /dest should be a new volume.

This can be run to validate the volume backup.

docker run \
  -it \
  -v application_backup:/backup \
  busybox /bin/sh

Once in the container, check the contents of /backup.

Please reach out to us if you see issues.