All docker files look something like this
services:
service_name:
image: author/project:latest
container_name: service_name
volumes:
- service_data:/app/data/
volumes:
service_data:
Yes, this makes the data to persist, but it creates a directory with a random name inside /var/lib/docker/volumes/
This makes it really hard to actually have ownership of the data of the service (for example to create backups, or to migrate to another host)
Why is it standard practice to use this instead of having a directory mounted inside at the same level you have your docker-compose.yml?
Like this - ./service_data:/app/data
All of mine use bind mounts so I can just tar-gz the whole deploy folder for backups and migrations. For volumes that connect to remote shares (SMB, NFS, etc) I use named volumes and let Docker take care of their lifecycle.
If named docker volumes would let me specify the local filesystem location, I’d use them. As-is, I rarely do.