Description

Windows 10 and Server 2016 RS4 (upcoming update to Windows due 18/03) will bring support for Unix Sockets (address family AF_UNIX). If we could support them in Moby, this could bring better feature parity with Linux, and it would make it easier for users of WSL. There are 2 levels of support we can achieve:

Make docker daemon on Windows listen on a Unix socket - the easy stuff

The same way as we do on linux (listening on /var/run/docker.sock), we could listen on c:\ProgramData\Docker\docker.sock (or any file path passed trough the --HOST flag). This would allow WSL users to connect to the daemon without having to expose anything trough TCP. This would also make it easier for admins to secure access to the daemon (using ntfs rights).

This could be done easily entirely in the Moby code-base.

Make Unix socket files bind-mountable in containers - the not so easy one

The goal here is to make it easy to bind mount a Unix Socket in a container (windows or lcow), the same way that we do on Linux. It would for exemple allow to bind mount Docker socket itself inside a container (windows or lcow), like many Linux containers do (and as we do ourself with Docker EE).

This might require some additional work on Windows HCS, but we should ask for confirmation from Microsoft.