systemd: please stop trying to take over the world :)

[Lennart Poettering]

On Tue, 14.06.11 12:17, Denys Vlasenko (dvlasenk at redhat.com) wrote:

> 
> On Tue, 2011-06-14 at 09:42 +0200, Lennart Poettering wrote:
> > On Mon, 13.06.11 18:01, Denys Vlasenko (dvlasenk at redhat.com) wrote:
> > > Maybe. It's not up to a piece of software to decide.
> > > In Unix, admins should have power to decide, not programs.
> > > Programs provide the means, they don't dictate policies.
> > 
> > Dude, systemd requires the functionality of the three modules it loads
> > explicitly.
> 
> systemd requires ipv6.

No it doesn't. 

All it does is make use of IPv6 if it is available (where available
means: if compiled in to the kernel or compiled as kmod and not
blacklisted). It requires the kernel module to be loaded properly at
boot to make use of that, hence it will try loading it, unless it is
explicitly blacklisted.

> And you pitch systemd to be used by embedded devices.

Yes, I do.

> Do you really think all embedded devices will be happy with having such
> an arbitrary requirement? Heck, I know embedded device people who remove
> even ipv4!

I said multiple times explicitly that systemd explicitly supports
IPv6-less systems.

> > If you
> > use daemontools you also need an init system, and boot scripts, and
> > everything else. So yeah, if you compare systemd and
> > daemontools+sysvinit+initscripts then, hell yeah, I can beat that.
> 
> This is not true.

It is.

> daemontools can be set up in a way than most init scripts are
> no longer necessary. It also achieves parallelized start.

This is bogus.

> It can also be used as an init replacement, but unlike systemd, it does
> not make it a requirement.
> 
> On my home machine I use a separate init (which does only child
> reaping), daemontools, and a very small set of init scripts (yes,
> horror, shell scripts). It starts in about 3 seconds. The system fully
> booted to text mode uses 20 megs of RAM total, all processes plus
> kernel, but excluding fs cache.

Good for you, but what does that have to do with Fedora?

> You can't beat that. In fact, you are yet to reply why systemd uses
> eleven megs of RAM all by itself.

Hey, read my mails: SELinux policy, SELinux policy, SELinux policy,
SELinux policy, SELinux policy.

> > > > Hmm? systemd is an init system, so it is of course PID 1.
> > > 
> > > Again. *Why it has to have PID 1* to spawn and control services?
> > > Can you please answer this?
> > 
> > Yupp, read up on Unix. Only PID 1 gets SIGCHLD for daemonized
> > processes.
> 
> Why service daemon needs to receive death notifications from daemonized
> processes?

To be able to supervise them? That's a key feature of supervision of
services: that you know when a daemon is gone, and know the exit code
and whether it crashed or not.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.