systemd has a behavior that is very nice for containers. If you send it
SIGRTMIN+3 (37 on some Linux systems), it will halt the machine (see
Further, if the env var "container" is set, systemd will actually exit.
9001-systemd-sigrtmin3-compat.diff adds this functionality to runit.
Prior to this, runit would of course just sit and spin after entering
stage 3 (its halt/shutdown/reboot target). Now if the env var
"container" is set, runit will exit. Plus runit can be signaled by
Docker (or whatever container manager) to shutdown immediately via
(Also, this commit adds the custom "emulab" bit into the package version