I’m a beginner of Docker. When I read about docker’s union file system, I was wondering about "Is the UFS concept only exist in Docker?"
>Solution :
Union mounts of various kinds have been around for a long time, they are really not a novel idea.
UnionFS is but one implementation of this idea and has been developed independently of Docker.
Docker actually uses various implementations of this idea, depending on what’s available and configured: AUFS, OverlayFS