Re: [gentoo-amd64] Please get me straight about sysvinit vs. systemd, udev vs eudev vs mdev, virtuals and other things...

[Canek Peláez Valdés]

On Mon, Mar 3, 2014 at 11:15 AM, Tanstaafl <tanstaafl@×××××××××××.org> wrote:
> On 3/2/2014 1:10 PM, Rich Freeman <rich0@g.o> wrote:
>> The big change in udev-210 is how persistent network device names are
>> implemented. The file that implements the rules is changing names,
>> which has an impact on your if you're trying to override it (your
>> override will no longer work if you don't change the name to follow
>> suit). Also, the new rule file now pulls in config settings from a
>> file that contains "systemd" in the filename.
>
>  <snip>
>
>> The file contains systemd in the name because it is also used by
>> systemd for network settings.
>
> Well... !?@?#?$?%
>
> Here we go again. Talk about 'a driving force to subsume everything it
> touches'!?

The networkd simple network manager is a new development in systemd,
not udev. They saw that both could share some configs, so they used
the directory under /etc that the whole project (systemd) uses. That's
all.

> So, "we use some files, so we change the name of every file we use to have
> our name in it?"

They *added* new configuration options, and udev (as part of the
systemd project) *followed through*.

> In other words... why stop at that one file?
>
> How much sense does *that* make? Seriously, that *really* irks me...

All the sense in the world, if you actually read the code and see how
the new networkd works.

> I think I'll go and Prepend 'Charles-' to the name of every document I've
> ever created... can anyone say 'egotistical'?

The project (like it or not) is called systemd. They are using the
/etc/systemd directory for configuration (as per long Unix tradition).
They haven't moved /etc/udev to /etc/systemd/udev for backwards
compatibility, but they could do it, and I think they *will* do it at
some point in the future. Again, nothing will change for udev, only
your machine will have a (*GASP!*) systemd directory somewhere.

>> Ok, just some definitions:
>> udev - the upstream project that you're familiar with - it has
>> recently merged with systemd, which has resulted in some changes that
>> some find objectionable (changes in install paths, incorporation of
>> systemd in file/path names, etc)
>
> This is I think the crux of the problem.
>
> Why did udev *merge* with systemd, if there is no long term goal of
> completely and totally subsuming it such that you cannot use udev without
> also using systemd?

This is FUD, Tanstaafl; they have promised that udev will be able to
work independently from systemd, and they have kept their promise.
They merged the two projects to share code (which they do) and because
systemd wants to be the basic plumbing of Linux; udev is obviously
needed for that.

But udev works without systemd, and it will continue to do so. The
*only* change is that now udev can use (not sure if it's mandatory)
some configuration files from /etc/systemd/network. Yo don't *need*
systemd to get udev working, and if you feel that a
/etc/systemd/network directory is going to give you the systemd
cooties, I personally think that's incredible obsessive. It's just a
directory *name*; it doesn't even contains executable code.

You can do the job (a simple sed before compilation is enough) to
exorcise the systemd name from all udev related files, but it's (IMHO)
idiotic. The project *is* systemd, like it or not; but it's Free
Software, go nuts and change all the "systemd" strings for "Charles"
if you so desire (I think a dev is doing that in an overlay).

> Imnsho, since it is a KERNEL thingie, it should have been maintained as a
> totally separate package, or just admit the long term goal and be done with
> it.

There is a kernel component and a userpace component for udev; they
are separated in the kernel and the systemd project. Also, the long
term goal is clear from the very beginning: systemd wants to be the
basic plumbing in Linux. That is orthogonal to having udev working
without systemd, and they have promised to support that, and it still
works that way and there is no sign whatsoever that it's going to
change.

If you get offended by a /etc/systemd/network directory, I think you
have more important issues, and they are unrelated to systemd/udev.

>> Udev is changing upstream - presumably because the new kernel features
>> are helpful in some way.  I haven't read the details.
>
> Now I'd really, really, REALLY like to hear what Linus thinks about
> systemd/udev NOW. The only things I can find from him are 4 or so years old.
> I can't imagine that stuff like this doesn't irk him too...

I don't think Linus opinion matters at all; people wanting to write
and use some free software projects will continue to do so
independently of what Linus, RMS, ESR, or the Flying Spaghetti Monster
says. Having said that, I would not be surprised if Linus actually
likes the idea of an standardized Linux plumbing, even if he dislikes
some particular implementation details, or its authors.

> Would someone who stands a chance at getting a response out of him *please*
> ping him for an opinion on this stuff? Blog or LKML post would be fine...

It would be interesting to know what he thinks; but either way it
doesn't really matters, like it didn't really mattered when he stopped
using GNOME, nor when he started using it again. Few users, if any,
stopped or started using GNOME because of that.

Regards.
-- 
Canek Peláez Valdés
Posgrado en Ciencia e Ingeniería de la Computación
Universidad Nacional Autónoma de México