Gentoo Announces Eudev Project -- Its Udev Fork

[GreatEmerald]

Yea, overall it looks like there are good reasons for a fork like that. Both projects are going different ways. I only hope that they will maintain a good relationship with one another to avoid any unnecessary duplicate work.

[waitejasoe]

the systemd crowd there was a promise to keep udev independent enough for others to use it without systemd.

[ryao]

that's not true though. You don't have to compile all of systemd to get udevd and friends (but unfortunately, you would still need the systemd sources, which includes things you don't need). with a few quick modifications, you can compile them independently; http://www.freedesktop.org/wiki/Soft.../MinimalBuilds it looks fairly simple to do, create a couple of (empty) .pc files, use PKG_CONFIG_PATH to point to them, then you can compile each component with 'make udevd' (etc).

anyway, that isn't really the crux of why they are forking from what i gather, just one issue (that sounds like it can already be easily resolved anyway and is already documented).

It is true that you can patch the build system to build udev independently, although that is a fragile hack. The Gentoo developers maintaining udev were not willing to maintain that outside of upstream and systemd upstream was not willing to do that. You could consider things from the perspective of what systemd's developers did and what the Gentoo udev maintainers did. Many of us did not like the end result and the only way that both groups (i.e. the existing maintainers and the rest of us) could be happy was for us to fork. Honestly, the existing Gentoo udev maintainers do not like having another udev in the tree, but their unwillingness to patch systemd udev to accommodate what the rest of us wanted necessitated it.

At this point, we have found plenty of decisions that the systemd developers made that we do not like, so the purpose of the fork has expanded beyond just patching a few things. In particular, we want to improve support for non-GNU userlands and tool chains, enforce peer review on all changes made and provide proper documentation of changes. That is in addition to fixing bugs that involve system configurations that Fedora does not use and making the build system simpler and more flexible. For the record, systemd's developers do not want any of this because their priorities differ from ours and that is okay.

[ninez]

So if I understand this right in systemd-devs pov if you wanted to use only udev you have to compile whole systemd at the same time. This would be ok binary distros like ubuntu and tho upstart, but not in source distros like gentoo. If I would want to use only udev with gentoo I don't want to compile something that are not needed, it's just a waste of time and resources of my own computer. And what Hubbs suggested with his patches is to add two configure flags that make possible to compile only udev.

that's not true though. You don't have to compile all of systemd to get udevd and friends (but unfortunately, you would still need the systemd sources, which includes things you don't need). with a few quick modifications, you can compile them independently; http://www.freedesktop.org/wiki/Soft.../MinimalBuilds it looks fairly simple to do, create a couple of (empty) .pc files, use PKG_CONFIG_PATH to point to them, then you can compile each component with 'make udevd' (etc).

anyway, that isn't really the crux of why they are forking from what i gather, just one issue (that sounds like it can already be easily resolved anyway and is already documented).

[ryao]

To complete the version:


Is that what eudev was all about? Running newer udev on very old kernel release?

It is one of the things that the notion of compatibility covers. Anyway, none of these kernels are particularly old. 2.6.32 is a LTS kernel that is used in RHEL6.

[finalzone]

For what it is worth, Koen tried yesterday to upstream a patch that I wrote to restore support for older kernels, but it was rejected. Kay Sievers wrote a longer email than what I quote here, but here is an abridged version:

http://lists.freedesktop.org/archives/systemd-devel/2012-December/007763.html

To complete the version:

We surely will not make anything harder than it needs to be, but
pretending bleeding edge tools will or should work on 2 years old
kernels is a promise we do not want to make with systemd/udev. In this
case, it would be the job of the libc, not the user of libc.

We surely support things the other way around, what the kernel is
doing, which is new kernels on old systems, but doing it both ways is
not really the goal for us.

Is that what eudev was all about? Running newer udev on very old kernel release?

[ryao]

For what it is worth, Koen tried yesterday to upstream a patch that I wrote to restore support for older kernels, but it was rejected. Kay Sievers wrote a longer email than what I quote here, but here is an abridged version:

We generally do not want to work around kernel or libc "bugs". So I'm
not interested in such a patch.

People who want or need to play these match-and-mix games with "new
userspace on old systems" should fix the dependencies where they are
missing, not expect "magic" workarounds from tools. There are many
subtle dependencies on various things which are not available on old
kernels and libc, this is just a very obvious one. We should not
pretend we support that model, we just don't. And it will get even
harder in the future, as we are trying to build a real OS now not a
"bag of bits".

http://lists.freedesktop.org/archives/systemd-devel/2012-December/007763.html

The two projects have orthogonal priorities. eudev favors long term compatibility as a modular component while systemd favors the single tree approach where support for older versions of components is pointless. Both have merits.

[ryao]

You mean these?

http://www.mail-archive.com/[email protected]/msg05287.html

So if I understand this right in systemd-devs pov if you wanted to use only udev you have to compile whole systemd at the same time. This would be ok binary distros like ubuntu and tho upstart, but not in source distros like gentoo. If I would want to use only udev with gentoo I don't want to compile something that are not needed, it's just a waste of time and resources of my own computer. And what Hubbs suggested with his patches is to add two configure flags that make possible to compile only udev.

That summarizes it.

[tuke81]

William Hubbs wrote patches for that which Lennart Poettering rejected.

You mean these?

http://www.mail-archive.com/[email protected]/msg05287.html

So if I understand this right in systemd-devs pov if you wanted to use only udev you have to compile whole systemd at the same time. This would be ok binary distros like ubuntu and tho upstart, but not in source distros like gentoo. If I would want to use only udev with gentoo I don't want to compile something that are not needed, it's just a waste of time and resources of my own computer. And what Hubbs suggested with his patches is to add two configure flags that make possible to compile only udev.

[ryao]

I don't read this as we will not accept patches that let it built by itself. If someone posted a patch like that and lennart or kay rejected it -i am not following systemd that much- then ok.

William Hubbs wrote patches for that which Lennart Poettering rejected.