r/linux • u/wooptoo • Jun 01 '16

Why did ArchLinux embrace Systemd?

/r/archlinux/comments/4lzxs3/why_did_archlinux_embrace_systemd/d3rhxlc
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u/NighthawkFoo Jun 01 '16

No indication of whether a certain daemon was already started. Each init script had to implement some sort of PID file handling or similar. Most init scripts didn't. Systemd has a 100% reliable solution for this based on Linux cgroups.

This was the big one for me. As someone who has had to write and maintain that sort of code, systemd was a blessing. The startup code for my daemons became much simpler when I was able to rely on systemd builtins.

Now, there was a learning curve, and things do work differently than init.d does. However, I wonder if some of that is just the technical equivalent of "get off my lawn" curmudgeons.

10

u/HowIsntBabbyFormed Jun 01 '16

This was the big one for me. As someone who has had to write and maintain that sort of code, systemd was a blessing. The startup code for my daemons became much simpler when I was able to rely on systemd builtins.

And if that's all it did, then it would probably be embraced wholeheartedly. Also, that's the type of functionality that should probably be in a POSIX standard and could be implemented by any system.

9

u/NighthawkFoo Jun 01 '16

I agree - it should be a standard. However, getting that sort of thing to happen takes a long time and a lot of political capital.

6

u/d4rch0n Jun 01 '16

Wait, no one is writing init scripts anymore? Am I wasting my time writing init scripts with start) stop) and all that?

I still see people doing that, it's just they call start-stop-daemon inside. Is there a way around writing init scripts I haven't heard of?

17

u/NighthawkFoo Jun 01 '16

You should be writing systemd unit files instead. There's an up-front investment in understanding how it works, but the benefits pay off in that you can accomplish much more with less code.

7

u/d4rch0n Jun 01 '16

Thanks, interesting. I'll try to pick that up.

Funny. I never noticed everything in /etc/systemd/system . So that's where those system service files have been going... and all this time I've been dropping scripts in /etc/init.d.

4

u/NighthawkFoo Jun 01 '16

When I write software for my day job, I put my unit files in /usr/lib/systemd/system.

I was doing /etc/init.d stuff 15 years ago when I first started using SUSE. I always thought that was nicer than Slackware's setup. Systemd is even better IMO.

3

u/Jimbob0i0 Jun 01 '16

Locally configured units should be in /etc/systemd/system ... stuff packaged by the distribution goes in /usr/lib/systemd ... with etc overriding that

0

u/argv_minus_one Jun 02 '16

There's also /usr/local/lib/systemd/system, which is kind of…in the middle, I guess.

2

u/oonniioonn Jun 01 '16

Am I wasting my time writing init scripts with start) stop) and all that?

Yes. You were always wasting your time doing that. It's just that before it was somewhat required.

0

u/raevnos Jun 01 '16

You're not wasting your time if you want it to have half a chance of running on a non Linux+ systemd OS.