On Fri, Dec 21, 2018 at 11:31:24AM -0800, Josh Triplett wrote: > Dmitry Bogatov wrote: > > Currently, init system packages (sysvinit-core, runit-init, > > systemd-sysv) are mutually exclusive -- each of them provides, > > among other, /sbin/init file and as such, conflicts with rest. > > > > This scheme has following drawbacks: > > > > * switching between init systems is destructive: > > once you switch, old /sbin/init is gone; should things go wrong, you > > have no easy recover via init=/sbin/old-init kernel option. > > > > Side note: switching from systemd is more safe, since systemd-sysv > > provides only link to /lib/systemd. > > sysvinit works similarly, with /lib/sysvinit/init. And GRUB has built-in > support for these. See /etc/grub.d/10_linux; if you have more than one > init system package installed, you will get separate boot options to > boot each of the inits that /sbin/init doesn't link to. > > You might consider submitting a patch to GRUB to add runit to that list,
I'm fine with taking care of this if somebody tells me which file to look for. (The current mapping is "sysvinit:/lib/sysvinit/init systemd:/lib/systemd/systemd upstart:/sbin/upstart"; the value needs to be a path that can be coinstalled with other init systems and that can be passed as the argument to "init=" on the kernel command line.) > or better yet making that behavior look for symlinks in /lib/inits/ or > similar and make an entry for every link that doesn't match /sbin/init. > (If you do so with fallbacks to the existing entries for systemd and > sysvinit, that'll make a transition simpler, and GRUB can remove the > fallbacks as soon as systemd and sysvinit add links in /lib/inits/.) This feels like overengineering and really not worth it; new inits don't come along all that often. I think we'd spend more time on transitional mechanics than we'd ever save. > (Meanwhile, I don't think it's necessarily a good idea to handle > /sbin/init and associated programs with alternatives, not least of which > because of the complications of switching the running system's init.) I quite agree. -- Colin Watson [cjwat...@debian.org]
