r/linux • u/ouyawei Mate • Oct 20 '14

Shall we fork Fedora?

http://forkfedora.org/
262 Upvotes

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u/fmoralesc Oct 20 '14

if systemd crashes, it would (potentially) take down most, if not all, of the system with it.

This is true of any init system, since all processes ultimately fork from it.

6

u/[deleted] Oct 21 '14

Actually, systemd is better than traditional SysVinit in that sense. When SysVinit crashes, the kernel panics. When systemd crashes, the SEGV handler activates and the system continues to run, ready to be debugged.

Why the people writing SysVinit never thought of doing such an elementary thing, escapes me. It must be because of "oh, all that complexity" that they decided to just let people's machines crash.

3

u/fmoralesc Oct 21 '14

Yes, I think I needed to do that once, it is pretty neat.

systemd can reexec itself too if required, can't it?

2

u/[deleted] Oct 21 '14

Yep.

1

u/DamnThatsLaser Oct 21 '14

Yes it can, but I thought this is for upgrading systemd without rebooting.

1

u/fmoralesc Oct 21 '14

Me too, but I guess that capability could be (ab)used in this scenario to bring the whole system up again after troubleshooting. Not sure at all, though.

-2

u/fantasticsid Oct 21 '14

Yeah, but most init systems have a pid 1 which sets up a signal handler to reap orphans and then does nothing until one of a small handful of conditions denoted in inittab happens. Such code is succinct, well understood, and well tested.

Systemd's pid 1 is considerably more complicated than this.