docker container to build statically linked tmux and screen
This builds fully statically linked tmux and screen binaries inside a docker container using musl library. These terminal multiplexors are not available under CoreOS and using a privileged container with such binaries for manual administartion is inconvinient.
Build the container:
docker build -t make-smplex directory
Run it with host volumes for storage and resulting binaries:
docker run -ti --rm -v /vol/smplex:/vol -v /opt/bin:/vol/bin make-smplex screen tmux
If successfull, this puts statically build screen and tmux under /opt/bin directory. If not, like when network connection to the servers with sources for the binaries and their dependent libraries is down, running the command again will resume from the point where it failed. If you need just one of multiplexers, drop other name from the command line.
Running screen or tmux under CoreOS from a ssh shell will terminate the multiplexer daemon process when the ssh connection terminates defeating the purpose of a persistent multiplexer. To workaround this the container provides together with the binaries the helper commands screen-resume and tmux-attach that start the multiplexer as a systemd service before resuming the screen session or attaching to tmux manager. So to login into, say, a tmux session on a CoreOS VM, just invoke ssh -t core@vm-name tmux-attach.