Linux Hotplug development

William Hubbs | 14 Aug 2012 20:01

killing udev for non-systemd systems

Hey Lennart, Kay and all,

On Wed, Aug 01, 2012 at 06:58:39PM +0200, Lennart Poettering wrote:
> Well, we intent to continue to make it possible to run udevd outside of
> systemd. But that's about it. We will not polish that, or add new
> features to that or anything.
> 
> OTOH we do polish behaviour of udev when used *within* systemd however,
> and that's our primary focus.
> 
> And what we will certainly not do is compromise the uniform integration
> into systemd for some cosmetic improvements for non-systemd systems.
> 
> (Yes, udev on non-systemd systems is in our eyes a dead end, in case you
> haven't noticed it yet. I am looking forward to the day when we can drop
> that support entirely.)

There are a number of reasons from what I see on my distro's development
list and from what I've seen insome patches proposed here, that everyone
isn't comfortable with systemd.

I thought the merge was more for administrative reasons, because there
is common source code between systemd and udev that you did not want to
provide as libraries.

Now though, with the attitude toward non-systemd systems that I see
above, I am starting to wonder.

You have taken a piece of software which is important to many linux
systems (udev) and merged it into an init system (systemd) which is not

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Colin Guthrie | 15 Aug 2012 00:20

Re: killing udev for non-systemd systems

'Twas brillig, and William Hubbs at 14/08/12 19:01 did gyre and gimble:
> You have taken a piece of software which is important to many linux
> systems (udev) and merged it into an init system (systemd) which is not
> used everywhere for a number of reasons. Now you are planning to kill
> udev for systems that do not use systemd. Why is that? Why are you
> saying that udev on non-systemd systems is a dead end?
> 
> Is there some alternative for non-systemd systems?

I think you're over reacting here.

The comment about it being a dead end is likely more related to how
device management and service management are *very* closely linked
sometimes - especially if you want to do things properly and non-racy
without lots of good will sprinkled over things in the hope that they
glue together OK. So to get the most out of udev and do things properly
you *need* to integrate properly with the init system. That's what I
read from the "dead end" statement anyway.

While I'm sure Lennart and Kay are looking forward to the day they can
drop any semblance of support for a separate udev entirely, I doubt very
much it's any time in the next little while (although I'm always
prepared to be proved wrong).

And besides, even if they do it's easy enough to fork using git and
maintain a separate version while still sharing most of the code if that
floats your boat.

I suspect in a few years time we'll see a much more focused systemd
world anyway and the people who are not using it now for whatever reason

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Lennart Poettering | 15 Aug 2012 12:52

Re: killing udev for non-systemd systems

On Tue, 14.08.12 13:01, William Hubbs (w.d.hubbs <at> gmail.com) wrote:

> > (Yes, udev on non-systemd systems is in our eyes a dead end, in case
> > you haven't noticed it yet. I am looking forward to the day when we
> > can drop that support entirely.)

> You have taken a piece of software which is important to many linux
> systems (udev) and merged it into an init system (systemd) which is not
> used everywhere for a number of reasons. Now you are planning to kill
> udev for systems that do not use systemd. Why is that? Why are you
> saying that udev on non-systemd systems is a dead end?

"looking forward to" is not "planning to". I'd appreciate if you
wouldn't twist my words.

> Is there some alternative for non-systemd systems?

We support running udev on non-systemd systems just fine. We will
continue to do so for some time, as long as there are enough reasons to
keep it (for example, relevant distributions need it). But eventually,
when those reasons are gone we'll drop it. And that's as specific as
I'll get. There are no plans beyond that.

And yes, I do believe that systemd is the way to go, and not
sysvinit. That's why I said "in our eyes non-systemd systems are a
dead-end" when it comes to udev. What do you expect me to say? Something
like "sysvinit is technically state of the art and has a bright future"?
Or maybe "openrc is awesome technological design and is what everybody
will use 5y from now"? Or maybe "Upstart is the most excellent current
design I have ever seen and is going to take the world by storm"? Nope,

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William Hubbs | 15 Aug 2012 19:13

Re: killing udev for non-systemd systems

On Wed, Aug 15, 2012 at 12:52:10PM +0200, Lennart Poettering wrote:
> On Tue, 14.08.12 13:01, William Hubbs (w.d.hubbs <at> gmail.com) wrote:
> 
> > > (Yes, udev on non-systemd systems is in our eyes a dead end, in case
> > > you haven't noticed it yet. I am looking forward to the day when we
> > > can drop that support entirely.)
> 
> > You have taken a piece of software which is important to many linux
> > systems (udev) and merged it into an init system (systemd) which is not
> > used everywhere for a number of reasons. Now you are planning to kill
> > udev for systems that do not use systemd. Why is that? Why are you
> > saying that udev on non-systemd systems is a dead end?
> 
> "looking forward to" is not "planning to". I'd appreciate if you
> wouldn't twist my words.

I didn't intend to twist your words; I was just looking for a
clarification. Maybe I should have worded this differently; sorry about
that.

> > Is there some alternative for non-systemd systems?
> 
> We support running udev on non-systemd systems just fine. We will
> continue to do so for some time, as long as there are enough reasons to
> keep it (for example, relevant distributions need it). But eventually,
> when those reasons are gone we'll drop it. And that's as specific as
> I'll get. There are no plans beyond that.

 Ok, that's cool.

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