Runit

runit is an init replacement with service monitoring. It can be used in conjunction with OpenRC as an alternative to sysvinit.

As PID 1
Runit can be used as the system init. To do this, simply add init=/sbin/runit-init to your bootloader's command line and reboot. You can leave sysvinit installed and go back to it at any time by reverting the change.

Out of the box, runit-init has a very minimal configuration which will only get you to a console login. All of your configured OpenRC services are still accessible though, and they can be automatically started on boot with a simple edit:

(If you're making the above change after the first reboot, there's no need to reboot twice for it to take effect - just run "rc default" manually.)

Runit isn't directly compatible with sysvinit's "telinit", "halt", "poweroff", "reboot" and "shutdown" commands, however, it's possible to emulate the interface they need with a simple script.

As a system service
Runit can supervise processes without running as init, or even necessarily as root:

OpenRC can start this for you using /etc/init.d/local (see /etc/local.d/README for more details):

External Resources
https://wiki.archlinux.org/index.php/runit https://forums.gentoo.org/viewtopic-p-7605220.html