[gentoo-user] Systemd as drop-in replacement for udev?

[gentoo-user] Systemd as drop-in replacement for udev?

[Róbert Čerňanský]

Hello all,

I am currently updating my system and Portage wants to replace udev
(204) with systemd (208).  My question is (hopefully) simple:

Can I use systemd as drop-in replacement for udev?  In other words, can
I pretend that systemd is udev and continue using OpenRC as with udev
itself?  I would then apply just udev 204 to 208 update instructions
(http://wiki.gentoo.org/wiki/Udev/upgrade).

I am using WindowMaker and systemd was pulled in by
gnome-settings-daemon which in turn was pulled in by gdm.  I would like
to stick with gdm.

Usually I feel pretty comfortable replacing one package with another if
Portage wants so (e.g. because they block each other) but in this case I
want to be extra careful.  I did not find a clear answer to this.
Usually people either migrate fully to systemd (replacing openrc) or
stays with udev + openrc.

Regards,
Robert


-- 
Róbert Čerňanský
E-mail: openhs@tightmail.com
Jabber: hs@jabber.sk

Re: [gentoo-user] Systemd as drop-in replacement for udev?

[Canek Peláez Valdés]

On Thu, Dec 5, 2013 at 2:36 PM, Róbert Čerňanský <openhs@tightmail.com> wrote:
> Hello all,
>
> I am currently updating my system and Portage wants to replace udev
> (204) with systemd (208).  My question is (hopefully) simple:
>
> Can I use systemd as drop-in replacement for udev?  In other words, can
> I pretend that systemd is udev and continue using OpenRC as with udev
> itself?  I would then apply just udev 204 to 208 update instructions
> (http://wiki.gentoo.org/wiki/Udev/upgrade).
>
> I am using WindowMaker and systemd was pulled in by
> gnome-settings-daemon which in turn was pulled in by gdm.  I would like
> to stick with gdm.
>
> Usually I feel pretty comfortable replacing one package with another if
> Portage wants so (e.g. because they block each other) but in this case I
> want to be extra careful.  I did not find a clear answer to this.
> Usually people either migrate fully to systemd (replacing openrc) or
> stays with udev + openrc.

I think that's the usual way; either switch completely to systemd, or
keep using OpenRC+udev (or OpenRC+eudev, or several other
combinations).

The GNOME stuff that requires systemd will not work under OpenRC from
3.10 on, you could get strange fails with gdm and
gnome-settings-daemon. If it's gdm-3.8, then I think you can use
systemd as udev replacement together with OpenRC, and I believe some
people did it successfully.

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

Re: [gentoo-user] Systemd as drop-in replacement for udev?

[Róbert Čerňanský]

On Thu, 5 Dec 2013 15:18:54 -0600
Canek Peláez Valdés <caneko@gmail.com> wrote:

> On Thu, Dec 5, 2013 at 2:36 PM, Róbert Čerňanský
> <openhs@tightmail.com> wrote:
> > Hello all,
> >
> > I am currently updating my system and Portage wants to replace udev
> > (204) with systemd (208).  My question is (hopefully) simple:
> >
> > Can I use systemd as drop-in replacement for udev?  In other words,
> > can I pretend that systemd is udev and continue using OpenRC as
> > with udev itself?  I would then apply just udev 204 to 208 update
> > instructions (http://wiki.gentoo.org/wiki/Udev/upgrade).
> >
> > I am using WindowMaker and systemd was pulled in by
> > gnome-settings-daemon which in turn was pulled in by gdm.  I would
> > like to stick with gdm.
> 
> The GNOME stuff that requires systemd will not work under OpenRC from
> 3.10 on, you could get strange fails with gdm and
> gnome-settings-daemon. If it's gdm-3.8, then I think you can use
> systemd as udev replacement together with OpenRC, and I believe some
> people did it successfully.

Thanks.  I have enabled openrc-force use flag found this in
gnome-settings-daemon emerge log, which confirms what you have said:

"gnome-settings-daemon needs Systemd to be *running* for working
properly. Please follow the this guide to migrate:
http://wiki.gentoo.org/wiki/Systemd
You are enabling 'openrc-force' USE flag to skip systemd requirement,
this can lead to unexpected problems and is not supported neither by
upstream neither by Gnome Gentoo maintainers. If you suffer any problem,
you will need to disable this USE flag system wide and retest before
opening any bug report."

So the it is clear to me now.

I will try openrc-force as temporal solution until I'll find a new
display manager and give heart breaking good by to GDM.

Regards,
Robert


-- 
Róbert Čerňanský
E-mail: openhs@tightmail.com
Jabber: hs@jabber.sk

Re: [gentoo-user] Systemd as drop-in replacement for udev?

[Canek Peláez Valdés]

On Thu, Dec 5, 2013 at 4:26 PM, Róbert Čerňanský <openhs@tightmail.com> wrote:
> On Thu, 5 Dec 2013 15:18:54 -0600
> Canek Peláez Valdés <caneko@gmail.com> wrote:
>
>> On Thu, Dec 5, 2013 at 2:36 PM, Róbert Čerňanský
>> <openhs@tightmail.com> wrote:
>> > Hello all,
>> >
>> > I am currently updating my system and Portage wants to replace udev
>> > (204) with systemd (208).  My question is (hopefully) simple:
>> >
>> > Can I use systemd as drop-in replacement for udev?  In other words,
>> > can I pretend that systemd is udev and continue using OpenRC as
>> > with udev itself?  I would then apply just udev 204 to 208 update
>> > instructions (http://wiki.gentoo.org/wiki/Udev/upgrade).
>> >
>> > I am using WindowMaker and systemd was pulled in by
>> > gnome-settings-daemon which in turn was pulled in by gdm.  I would
>> > like to stick with gdm.
>>
>> The GNOME stuff that requires systemd will not work under OpenRC from
>> 3.10 on, you could get strange fails with gdm and
>> gnome-settings-daemon. If it's gdm-3.8, then I think you can use
>> systemd as udev replacement together with OpenRC, and I believe some
>> people did it successfully.
>
> Thanks.  I have enabled openrc-force use flag found this in
> gnome-settings-daemon emerge log, which confirms what you have said:
>
> "gnome-settings-daemon needs Systemd to be *running* for working
> properly. Please follow the this guide to migrate:
> http://wiki.gentoo.org/wiki/Systemd
> You are enabling 'openrc-force' USE flag to skip systemd requirement,
> this can lead to unexpected problems and is not supported neither by
> upstream neither by Gnome Gentoo maintainers. If you suffer any problem,
> you will need to disable this USE flag system wide and retest before
> opening any bug report."
>
> So the it is clear to me now.
>
> I will try openrc-force as temporal solution until I'll find a new
> display manager and give heart breaking good by to GDM.

You could *try* to run systemd and see if you like it.

Many of us do.

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

Re: [gentoo-user] Systemd as drop-in replacement for udev?

[J. Roeleveld]

On Fri, December 6, 2013 00:17, Canek Peláez Valdés wrote:
> On Thu, Dec 5, 2013 at 4:26 PM, Róbert Čerňanský
> <openhs@tightmail.com> wrote:
>> I will try openrc-force as temporal solution until I'll find a new
>> display manager and give heart breaking good by to GDM.
>
> You could *try* to run systemd and see if you like it.
>
> Many of us do.

For the option to try systemd, I would first require a detailed how-to on
how to switch back to OpenRC without requiring reverting to backups or
doing a full reinstall.

--
Joost

Re: [gentoo-user] Systemd as drop-in replacement for udev?

[Michael Hampicke]

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Am 06.12.2013 07:32, schrieb J. Roeleveld:
> On Fri, December 6, 2013 00:17, Canek Peláez Valdés wrote:
>> On Thu, Dec 5, 2013 at 4:26 PM, Róbert Čerňanský
>> <openhs@tightmail.com> wrote:
>>> I will try openrc-force as temporal solution until I'll find a new
>>> display manager and give heart breaking good by to GDM.
>>
>> You could *try* to run systemd and see if you like it.
>>
>> Many of us do.
> 
> For the option to try systemd, I would first require a detailed how-to on
> how to switch back to OpenRC without requiring reverting to backups or
> doing a full reinstall.
> 

Just remove "init=/usr/lib/systemd/systemd" from your kernel command
line, and you can boot your old openrc installation (if you did un
unmerge it)


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Re: [gentoo-user] Systemd as drop-in replacement for udev?

[Michael Hampicke]

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> 
> Just remove "init=/usr/lib/systemd/systemd" from your kernel command
> line, and you can boot your old openrc installation (if you did un
> unmerge it)
> 

That should mean: ..if you did not unmerge it.


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Re: [gentoo-user] Systemd as drop-in replacement for udev?

[J. Roeleveld]

On Fri, December 6, 2013 08:53, Michael Hampicke wrote:
>>
>> Just remove "init=/usr/lib/systemd/systemd" from your kernel command
>> line, and you can boot your old openrc installation (if you did un
>> unmerge it)
>>
>
> That should mean: ..if you did not unmerge it.
>
>

It doesn't seem that simple from the wiki-page on how to switch to systemd:
http://wiki.gentoo.org/wiki/Systemd

In the "conflicts" section there is mention of having to change syslog-ng
and cryptsetup.

I don't have a Gentoo box in front of me to check, but I think "udev" and
"systemd" can not be installed simultaneously.
Was this changed?

--
Joost

Re: [gentoo-user] Systemd as drop-in replacement for udev?

[Canek Peláez Valdés]

On Fri, Dec 6, 2013 at 12:32 AM, J. Roeleveld <joost@antarean.org> wrote:
> On Fri, December 6, 2013 00:17, Canek Peláez Valdés wrote:
>> On Thu, Dec 5, 2013 at 4:26 PM, Róbert Čerňanský
>> <openhs@tightmail.com> wrote:
>>> I will try openrc-force as temporal solution until I'll find a new
>>> display manager and give heart breaking good by to GDM.
>>
>> You could *try* to run systemd and see if you like it.
>>
>> Many of us do.
>
> For the option to try systemd, I would first require a detailed how-to on
> how to switch back to OpenRC without requiring reverting to backups or
> doing a full reinstall.

You don't need to use backups, much less a full reinstall. However,
several packages must be reemerged and a couple ones must be
uninstalled before you switch to systemd. Obviously, you need to do
the opposite to revert back to OpenRC.

Which packages must be reemerged and which ones must be uninstalled
depends on what do you have installed. It is mostly handled by
portage, though, so you don't need to worry about it.

If you unpack a stage3 tarball for a new installation, the only thing
you need to do to get systemd is to "emerge systemd" and change your
init line in your boot loader. Portage will uninstall udev for you,
and OpenRC will remain, but it would do nothing. The more things you
add to your system, the more packages will be affected by the change,
in either direction. Also, systemd requires more kernel configure
options enabled than OpenRC.

To change back, usually you will only need to unemerge systemd, emerge
udev, and perhaps USE="-systemd" emerge -uDNvp @world. Be warned that
the best thing to do is to do it from a LiveCD; if you boot with
systemd, and uninstalled it, I don't think the shutdown would be
clean.

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

Re: [gentoo-user] Systemd as drop-in replacement for udev?

[Tom Wijsman]

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On Fri, 06 Dec 2013 08:53:43 +0100
Michael Hampicke <mh@hadt.biz> wrote:

> That should mean: ..if you did not unmerge it.

sys-apps/openrc is part of the @system set for the time being; if you
try to unmerge it you will be presented with a warning, if you go ahead
you break things like Portage and more because at this point in time
sys-apps/openrc brings the file 'functions.sh' which contains some
crucial functions used by those other packages.

This is tracked in https://bugs.gentoo.org/show_bug.cgi?id=373219

-- 
With kind regards,

Tom Wijsman (TomWij)
Gentoo Developer

E-mail address  : TomWij@gentoo.org
GPG Public Key  : 6D34E57D
GPG Fingerprint : C165 AF18 AB4C 400B C3D2  ABF0 95B2 1FCD 6D34 E57D

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[gentoo-user] Re: Systemd as drop-in replacement for udev?

[Jonathan Callen]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

On 12/06/2013 05:44 AM, J. Roeleveld wrote:
> On Fri, December 6, 2013 08:53, Michael Hampicke wrote:
>>> 
>>> Just remove "init=/usr/lib/systemd/systemd" from your kernel command line, and you can boot
>>> your old openrc installation (if you did un unmerge it)
>>> 
>> 
>> That should mean: ..if you did not unmerge it.
>> 
>> 
> 
> It doesn't seem that simple from the wiki-page on how to switch to systemd: 
> http://wiki.gentoo.org/wiki/Systemd
> 
> In the "conflicts" section there is mention of having to change syslog-ng and cryptsetup.
> 
> I don't have a Gentoo box in front of me to check, but I think "udev" and "systemd" can not be
> installed simultaneously. Was this changed?
> 
> -- Joost
> 
> 
> 
> 

Udev as installed by sys-fs/udev is *exactly* the same as udev installed by sys-apps/systemd,
except that the latter installs more files.  It is very much possible to switch to systemd as your
udev provider without using the rest of systemd.

- -- 
Jonathan Callen
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Re: [gentoo-user] Re: Systemd as drop-in replacement for udev?

[Róbert Čerňanský]

On Sat, 07 Dec 2013 01:43:37 -0500
Jonathan Callen <jcallen@gentoo.org> wrote:

> Udev as installed by sys-fs/udev is *exactly* the same as udev
> installed by sys-apps/systemd, except that the latter installs more
> files.  It is very much possible to switch to systemd as your udev
> provider without using the rest of systemd.

That's what I have suspected but I did not find anybody that has
experience with such setup.  If anyone tried it, comments are welcomed.

In the meantime I have settled with lightdm instead of gdm and stay
with sys-fs/udev.

Robert


-- 
Róbert Čerňanský
E-mail: openhs@tightmail.com
Jabber: hs@jabber.sk