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Old 06-30-2016, 01:35 PM   #1
biosboy4
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init vs systemd


Hello,

From my understanding, a replacement for the aged init system is needed/inevitable. However, systemd (it's "successor") seems to essentially be the opposite of the *nix philosophy which is building software to do one thing, and one thing well. Instead, systemd seems to want to do many, many things.

That being said, it looks like it could be too late to stop systemd. Now being a person that doesn't know exactly how init or systemd works, what is the forecast on comparability between all the forks generated by init vs systemd? Also, is there some other replacement for the old init system that could "stand up" to systemd?

Just curious..

thanks guys,

biosboy4
 
Old 06-30-2016, 01:41 PM   #2
Emerson
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Define init, there are several. For instance I'm happy with OpenRC.
 
Old 06-30-2016, 01:51 PM   #3
biosboy4
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SysV, Openrc, systemd, other init systems.. I'm just having trouble understanding how a system (init) that simply runs scripts from a dir needs to be replaced by something so anti-*nix like systemd..
 
Old 06-30-2016, 01:57 PM   #4
Emerson
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This is subject of many hot debates on all/any Linux forums. Do we really need another thread?
 
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Old 06-30-2016, 02:06 PM   #5
biosboy4
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Quote:
This is subject of many hot debates on all/any Linux forums. Do we really need another thread?
I don't see what the harm is, and it is bound to educate at least a few dozen regulars here at LQ. (including myself)

init systems basically just run startup scripts, right? Why does that supposedly need replacing so bad? and how in the world is it breaking compatibility for things like gnome? If it's because it has it's hands on things that should be handled by some other part of gnu, then I'm pretty sure I'm going to stop using it since that would be against my religion.

Last edited by biosboy4; 06-30-2016 at 02:09 PM.
 
Old 06-30-2016, 02:12 PM   #6
Emerson
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Gnome is growing monolithic, it is built with systemd being part of it. There is a project to run Gnome without systemd, so it is possible, despite what they tell to us.
I have systemd in only one of my computers - RPi running Debian. And the wonderful feature of systemd to keep processes alive even if they crash has rendered this RPi unusable. Respawning crippled process is taking all resources of poor RPi and it never finishes booting.
 
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Old 06-30-2016, 02:22 PM   #7
biosboy4
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Makes sense! So I can see "init vs systemd" as being a form of preference/need more than anything. A giant server with way too many resources could benefit from systemd to keep it's processes alive after crashes, or perhaps one is cramming in all they can to their servers and would prefer a leaner approach like traditional init.

Actually.. now that I think about it, scripting something to restart selected/critical services should probably take up so fewer resources than systemd seems to be demanding from your rpi.
 
Old 06-30-2016, 02:36 PM   #8
Emerson
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Actually, if a process crashes then it should be fixed instead of being constantly restarted. Or say, you have a network service that comes under attack, it crashes as a result. Now, systemd restarts it happily, so bad guys can try again ...
 
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Old 06-30-2016, 02:48 PM   #9
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Gotcha! Bad systemd.... Ok.

Since I am getting ready to build a network in a terribly old x86-box (literally), I'm going to opt for an init system, but which one?

Does Devuan have a minimal installer or should I Arch/Gentoo/LFS/TinyCore something up?

The box is a P4 supporting virtualization and it will have a gig or 2 of ram.
 
Old 06-30-2016, 02:56 PM   #10
notKlaatu
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Init systems are no different than any other software. They are things that you install (or have installed for you, depending on how much you let you distribution do for you); the difference is, init runs very early in the boot process (and as part of the boot process).

I've had success with [well-implemented] systemd on appliance / kiosk style boxen that I've built for public use; it handles reboots quickly and efficiently (especially if I prune it), its init scripts are as easy to write as anything else (easier, in some cases, since you often don't have to handle conditions yourself), and it relaunches a crashed daemon, keeping the need for human monitoring pretty low. All of this could be implemented manually, but it's nice to have the option to just let something else deal with it.

On my own computers, I run a BSD-style init on Slackware and am perfectly happy with it. It's easy to change, easy to manage, the way it works is easy to understand and debug. All the parts are exposed and easy to comprehend and manage, which is one of the many reasons I switched to unix in the first place: I want to be able to see the way my computer works, and to be able to fix it when it breaks. I can do that on systemd, but most of the commands involved are basically magic that I don't really know enough about (although if I wanted to know more, I could read the source code and learn). So for myself, I prefer BSD-style init.

I also use ninit on one of my computers. I wrote a tutorial on using ninit so others can try it, too. If you have never changed your init system for fun or education, then you probably don't *actually* need to worry yourself about how your init system works in the first place; it's all equally magical to you.
 
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Old 06-30-2016, 03:27 PM   #11
biosboy4
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Thank you sir,

I think I will probably just go with DSL for my little project since I'm already used to Debian and I think I will prefer regular init.
I know DSL hsn't been really updated recently, but I think I should be able to get vswitches n things installed on there just fine.

Though I do wonder how it's virtualization support is..
 
Old 06-30-2016, 04:38 PM   #12
ReaperX7
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With init's like sysvinit, runit, etc. you use more modular and interchangeable parts like ConsoleKit2, eudev, perp, etc. to accomplish the same tasks. Each part does its own job as an independent service daemon.

To be fair, sysvinit+OpenRC+s6 is probably the most advanced setup for init with parallel startup and supervision.

Granted systemd does a lot, realistically it's extraneous parts have been supplicanted by ConsoleKit2 with eudev making it really unnecessary to the whole unless you really want to run GNOME and even that can be done without systemd to an extent.
 
Old 07-02-2016, 06:32 PM   #13
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Personally, I prefer systemd. But I think a big part of it is that I learned Linux just in the last few years, as the switch was taking place, and never got to know the System V style ones as well. People who learned it earlier may tend to notice the features they lose, and not the ones they gain, and vice versa in my case.

I've always found configuring systemd logical and consistent, and it has never broken on me. Anytime I need a feature, it's always implemented. A lot of little things just make more sense, for example spawning ttys as needed instead of listing them in inittab. Do I like the idea of it taking over cron, syslog, and xinetd? Not really, but if it makes it faster (which I'm told it does) and makes life easier for developers so they can work on bugs and the software we actually use to be productive (which I'm told it does) then I'm fine with it, especially since cron works the same as always, and journalctl is actually quite nice once you get used to it (obviously, journald still isn't up to snuff for a lot of networks, but it's perfect for home use).

The biggest problem I've had with systemd is inferior documentation in some areas.
 
Old 07-02-2016, 07:54 PM   #14
offgridguy
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Quote:
Originally Posted by biosboy4 View Post
Hello,

From my understanding, a replacement for the aged init system is needed/inevitable. However, systemd (it's "successor") seems to essentially be the opposite of the *nix philosophy which is building software to do one thing, and one thing well. Instead, systemd seems to want to do many, many things.

That being said, it looks like it could be too late to stop systemd. Now being a person that doesn't know exactly how init or systemd works, what is the forecast on comparability between all the forks generated by init vs systemd? Also, is there some other replacement for the old init system that could "stand up" to systemd?

Just curious..

thanks guys,

biosboy4
Interesting article here about this debate.
http://www.tecmint.com/systemd-replaces-init-in-linux/
 
Old 07-02-2016, 08:09 PM   #15
Emerson
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See the table systemd vs. init (link in above post). It is horrible, why an init system wants to do everything? I want it be modular, I use services/daemons I need, period. BTW, OpenRC allows parallel booting and interactive booting, so that table is not entirely correct.

Bailing now. Can't stand the systemd.
 
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