Why Can’t Docker Access My Custom Root Directory?

If you installed Docker using Snap, it could be causing problems. Snap has strict confinement which often prevents access to directories like /data. Try moving your data directory to /mnt/data, or better yet, install Docker through the official repositories.

Just a heads up, trying to mount your whole root directory isn't a good idea. You should only mount specific directories. For example, you could use the command `-v /data:/data` to mount just the /data directory.

It sounds like you're missing some details about your setup. What errors are you encountering? Sharing your Dockerfile or the commands you're using would really help us troubleshoot better.

Make sure the account that's running Docker has the right permissions for the /data directory. If you had to elevate permissions to create it, then you might also need to adjust permissions for Docker to access it.

If you're using Docker Desktop on Linux, that might be the issue. Docker runs in a virtual machine, so you'll need to share directories for them to be accessible. If that's the case, consider switching to the regular Docker engine instead of Docker Desktop.