[gentoo-user] Change from udev to eudev?

[gentoo-user] Change from udev to eudev?

[wabe]

Hi,

emerge wants to install eudev. Now I wonder if this is ok 
and if so, how I can do this without breaking my system.

Any help is greatly appreciated.

This is the output from emerge:


~# emerge -avuD --verbose-conflicts --keep-going --changed-use --with-bdeps=y --backtrack=999 @world

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild  N     ] sys-fs/eudev-3.1.5::gentoo  USE="hwdb kmod -introspection -rule-generator (-selinux) -static-libs {-test}" ABI_X86="(64) -32 (-x32)" 1.705 KiB
[ebuild  N     ] dev-libs/libgudev-230::gentoo  USE="-debug -introspection -static-libs" ABI_X86="(64) -32 (-x32)" 0 KiB
[blocks B      ] sys-fs/udev ("sys-fs/udev" is blocking sys-fs/eudev-3.1.5)
[blocks B      ] sys-fs/udev[gudev(-)] ("sys-fs/udev[gudev(-)]" is blocking dev-libs/libgudev-230)
[blocks B      ] dev-libs/libgudev ("dev-libs/libgudev" is blocking sys-fs/udev-216)

Total: 2 packages (2 new), Size of downloads: 1.705 KiB
Conflict: 3 blocks (3 unsatisfied)

 * Error: The above package list contains packages which cannot be
 * installed at the same time on the same system.

  (sys-fs/udev-216:0/0::gentoo, installed) pulled in by
    >=sys-fs/udev-208-r1:0/0[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?,gudev(-),introspection(-)?,static-libs?] (>=sys-fs/udev-208-r1:0/0[abi_x86_64(-),gudev(-)]) required by (virtual/libgudev-215-r3:0/0::gentoo, installed)
    >=sys-fs/udev-208-r1:0/0[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?,static-libs?] (>=sys-fs/udev-208-r1:0/0[abi_x86_64(-)]) required by (virtual/libudev-215-r1:0/1::gentoo, installed)

  (dev-libs/libgudev-230:0/0::gentoo, ebuild scheduled for merge) pulled in by
    dev-libs/libgudev:0/0[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?,introspection?,static-libs?] (dev-libs/libgudev:0/0[abi_x86_64(-)]) required by (virtual/libgudev-215-r3:0/0::gentoo, installed)

  (sys-fs/eudev-3.1.5:0/0::gentoo, ebuild scheduled for merge) pulled in by
    >=sys-fs/eudev-1.3 required by (virtual/udev-215:0/0::gentoo, installed)
    >=sys-fs/eudev-1.3:0/0[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?,static-libs?] (>=sys-fs/eudev-1.3:0/0[abi_x86_64(-)]) required by (virtual/libudev-215-r1:0/1::gentoo, installed)


--
Regards
wabe

Re: [gentoo-user] Change from udev to eudev?

[R0b0t1]

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Unmerge udev.

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Re: [gentoo-user] Change from udev to eudev?

[Dale]

wabe wrote:
> Hi,
>
> emerge wants to install eudev. Now I wonder if this is ok 
> and if so, how I can do this without breaking my system.
>
> Any help is greatly appreciated.
>
> This is the output from emerge:
>
>
> ~# emerge -avuD --verbose-conflicts --keep-going --changed-use --with-bdeps=y --backtrack=999 @world
>
> These are the packages that would be merged, in order:
>
> Calculating dependencies... done!
> [ebuild  N     ] sys-fs/eudev-3.1.5::gentoo  USE="hwdb kmod -introspection -rule-generator (-selinux) -static-libs {-test}" ABI_X86="(64) -32 (-x32)" 1.705 KiB
> [ebuild  N     ] dev-libs/libgudev-230::gentoo  USE="-debug -introspection -static-libs" ABI_X86="(64) -32 (-x32)" 0 KiB
> [blocks B      ] sys-fs/udev ("sys-fs/udev" is blocking sys-fs/eudev-3.1.5)
> [blocks B      ] sys-fs/udev[gudev(-)] ("sys-fs/udev[gudev(-)]" is blocking dev-libs/libgudev-230)
> [blocks B      ] dev-libs/libgudev ("dev-libs/libgudev" is blocking sys-fs/udev-216)
>
> Total: 2 packages (2 new), Size of downloads: 1.705 KiB
> Conflict: 3 blocks (3 unsatisfied)
>
>  * Error: The above package list contains packages which cannot be
>  * installed at the same time on the same system.
>
>   (sys-fs/udev-216:0/0::gentoo, installed) pulled in by
>     >=sys-fs/udev-208-r1:0/0[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?,gudev(-),introspection(-)?,static-libs?] (>=sys-fs/udev-208-r1:0/0[abi_x86_64(-),gudev(-)]) required by (virtual/libgudev-215-r3:0/0::gentoo, installed)
>     >=sys-fs/udev-208-r1:0/0[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?,static-libs?] (>=sys-fs/udev-208-r1:0/0[abi_x86_64(-)]) required by (virtual/libudev-215-r1:0/1::gentoo, installed)
>
>   (dev-libs/libgudev-230:0/0::gentoo, ebuild scheduled for merge) pulled in by
>     dev-libs/libgudev:0/0[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?,introspection?,static-libs?] (dev-libs/libgudev:0/0[abi_x86_64(-)]) required by (virtual/libgudev-215-r3:0/0::gentoo, installed)
>
>   (sys-fs/eudev-3.1.5:0/0::gentoo, ebuild scheduled for merge) pulled in by
>     >=sys-fs/eudev-1.3 required by (virtual/udev-215:0/0::gentoo, installed)
>     >=sys-fs/eudev-1.3:0/0[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?,static-libs?] (>=sys-fs/eudev-1.3:0/0[abi_x86_64(-)]) required by (virtual/libudev-215-r1:0/1::gentoo, installed)
>
>
> --
> Regards
> wabe
>
>


I switched mine back when eudev was new and not even stable yet.  It was
as simple as unmerge udev and emerge eudev.  I don't recall even doing a
reboot, which I rarely do here anyway. 

Dale

:-)  :-) 

Re: [gentoo-user] Change from udev to eudev?

[wabe]

Dale <rdalek1967@gmail.com> wrote:

> wabe wrote:
> > Hi,
> >
> > emerge wants to install eudev. Now I wonder if this is ok 
> > and if so, how I can do this without breaking my system.
> >
> > Any help is greatly appreciated.
> >
> > This is the output from emerge:
[...]
> I switched mine back when eudev was new and not even stable yet.  It
> was as simple as unmerge udev and emerge eudev.  I don't recall even
> doing a reboot, which I rarely do here anyway. 

THX for your answer.

That's also what I normally do in such a case but I was not sure if
the systems keeps running when I remove udev. I will make a backup 
before I remove udev. Then I should be on the safe side.

But I wonder why portage wanna change udev to eudev on my system. It
seems that this is not the case for everyone else. I'm using a stable
hardened gentoo system and did not change USE flags or other settings.
Just started my regular update process.

@R0b0t1: THX also for your answer.

--
Regards
wabe

Re: [gentoo-user] Change from udev to eudev?

[Dale]

wabe wrote:
> Dale <rdalek1967@gmail.com> wrote:
>
>> wabe wrote:
>>> Hi,
>>>
>>> emerge wants to install eudev. Now I wonder if this is ok 
>>> and if so, how I can do this without breaking my system.
>>>
>>> Any help is greatly appreciated.
>>>
>>> This is the output from emerge:
> [...]
>> I switched mine back when eudev was new and not even stable yet.  It
>> was as simple as unmerge udev and emerge eudev.  I don't recall even
>> doing a reboot, which I rarely do here anyway. 
> THX for your answer.
>
> That's also what I normally do in such a case but I was not sure if
> the systems keeps running when I remove udev. I will make a backup 
> before I remove udev. Then I should be on the safe side.
>
> But I wonder why portage wanna change udev to eudev on my system. It
> seems that this is not the case for everyone else. I'm using a stable
> hardened gentoo system and did not change USE flags or other settings.
> Just started my regular update process.
>
> @R0b0t1: THX also for your answer.
>
> --
> Regards
> wabe
>
>


Add the -t option and it should show what is pulling it in.  I don't
know why, I always forget to add that when something confusing happens
on my end but I always think about it when it happens to someone else. 
I think it could be age related.  lol 

If I recall correctly, I was logged into KDE when I did mine.  Keep in
mind, it just adds new stuff that you connect.  If for example you plug
in something during the switch, that could cause it to not recognize the
device.  As long as you don't connect/disconnect anything, it should
work fine.  The only problem I might could see is if you have a
mouse/keyboard with a flaky connection.   Likely a rare thing to happen
tho, without you already noticing. 

Dale

:-)  :-) 

Re: [gentoo-user] Change from udev to eudev?

[wabe]

Dale <rdalek1967@gmail.com> wrote:

> wabe wrote:
> > Dale <rdalek1967@gmail.com> wrote:
> >  
> >> wabe wrote:  
> >>> Hi,
> >>>
> >>> emerge wants to install eudev. Now I wonder if this is ok 
> >>> and if so, how I can do this without breaking my system.
> >>>
> >>> Any help is greatly appreciated.
> >>>
> >>> This is the output from emerge:  
> > [...]  
> >> I switched mine back when eudev was new and not even stable yet.
> >> It was as simple as unmerge udev and emerge eudev.  I don't recall
> >> even doing a reboot, which I rarely do here anyway.   
> > THX for your answer.
> >
> > That's also what I normally do in such a case but I was not sure if
> > the systems keeps running when I remove udev. I will make a backup 
> > before I remove udev. Then I should be on the safe side.
> >
> > But I wonder why portage wanna change udev to eudev on my system. It
> > seems that this is not the case for everyone else. I'm using a
> > stable hardened gentoo system and did not change USE flags or other
> > settings. Just started my regular update process.
> >
> > @R0b0t1: THX also for your answer.
> >
> > --
> > Regards
> > wabe
> >
> >  
> 
> 
> Add the -t option and it should show what is pulling it in.  I don't
> know why, I always forget to add that when something confusing happens
> on my end but I always think about it when it happens to someone
> else. I think it could be age related.  lol 

Thanks for the hint. I will use -t from now on. Unfortunately it didn't
gave me more information than I already had from using some "equery d"
commands.

Whatever. I unmerged udev and merged eudev. Now everything seems to be
ok on my gentoo system.

--
Regards
wabe

Re: [gentoo-user] Change from udev to eudev?

[Marc Joliet]

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On Wednesday 08 June 2016 02:43:07 wabe wrote:
[...]
>But I wonder why portage wanna change udev to eudev on my system. It
>seems that this is not the case for everyone else. I'm using a stable
>hardened gentoo system and did not change USE flags or other settings.
>Just started my regular update process.
[...]

My suspicion is that libgudev is in @world (or in a set your created yourself).  
Perhaps try "emerge --deselect libgudev"; if it works, the hard blocker should 
become a soft blocker ("b" instead of "B"), which portage can resolve by itself.

HTH
=2D- 
Marc Joliet
=2D-
"People who think they know everything really annoy those of us who know we
don't" - Bjarne Stroustrup


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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">
<html><head><meta name="qrichtext" content="1" /><style type="text/css">
p, li { white-space: pre-wrap; }
</style></head><body style=" font-family:'DejaVu Sans Mono'; font-size:11pt; font-weight:400; font-style:normal;">
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">On Wednesday 08 June 2016 02:43:07 wabe wrote:</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">[...]</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;But I wonder why portage wanna change udev to eudev on my system. It</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;seems that this is not the case for everyone else. I'm using a stable</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;hardened gentoo system and did not change USE flags or other settings.</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;Just started my regular update process.</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">[...]</p>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; ">&nbsp;</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">My suspicion is that libgudev is in @world (or in a set your created yourself).  Perhaps try &quot;emerge --deselect libgudev&quot;; if it works, the hard blocker should become a soft blocker (&quot;b&quot; instead of &quot;B&quot;), which portage can resolve by itself.</p>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; ">&nbsp;</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">HTH</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">-- </p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">Marc Joliet</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">--</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&quot;People who think they know everything really annoy those of us who know we</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">don't&quot; - Bjarne Stroustrup</p>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; ">&nbsp;</p></body></html>
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On Wednesday 08 June 2016 02:43:07 wabe wrote:
[...]
>But I wonder why portage wanna change udev to eudev on my system. It
>seems that this is not the case for everyone else. I'm using a stable
>hardened gentoo system and did not change USE flags or other settings.
>Just started my regular update process.
[...]

My suspicion is that libgudev is in @world (or in a set your created yourself).  
Perhaps try "emerge --deselect libgudev"; if it works, the hard blocker should 
become a soft blocker ("b" instead of "B"), which portage can resolve by itself.

HTH
-- 
Marc Joliet
--
"People who think they know everything really annoy those of us who know we
don't" - Bjarne Stroustrup


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Re: [gentoo-user] Change from udev to eudev?

[wabe]

Marc Joliet <marcec@gmx.de> wrote:

> On Wednesday 08 June 2016 02:43:07 wabe wrote:
> [...]
> >But I wonder why portage wanna change udev to eudev on my system. It
> >seems that this is not the case for everyone else. I'm using a stable
> >hardened gentoo system and did not change USE flags or other
> >settings. Just started my regular update process.  
> [...]
> 
> My suspicion is that libgudev is in @world (or in a set your created
> yourself). Perhaps try "emerge --deselect libgudev"; if it works, the
> hard blocker should become a soft blocker ("b" instead of "B"), which
> portage can resolve by itself.

It isn't listed in /var/lib/portage/world. But it's a dependency of
about a dozen of packages on my system.

At the moment I don't have enough time to search for the reason why 
portage wants to install eudev. So I simply unmerged udev and 
installed eudev.

--
Regards
wabe

Re: [gentoo-user] Change from udev to eudev?

[waltdnes]

On Mon, Jun 13, 2016 at 12:06:18AM +0200, wabe wrote
> Marc Joliet <marcec@gmx.de> wrote:
> 
> > On Wednesday 08 June 2016 02:43:07 wabe wrote:
> > [...]
> > >But I wonder why portage wanna change udev to eudev on my system. It
> > >seems that this is not the case for everyone else. I'm using a stable
> > >hardened gentoo system and did not change USE flags or other
> > >settings. Just started my regular update process.  
> > [...]
> > 
> > My suspicion is that libgudev is in @world (or in a set your created
> > yourself). Perhaps try "emerge --deselect libgudev"; if it works, the
> > hard blocker should become a soft blocker ("b" instead of "B"), which
> > portage can resolve by itself.
> 
> It isn't listed in /var/lib/portage/world. But it's a dependency of
> about a dozen of packages on my system.
> 
> At the moment I don't have enough time to search for the reason why 
> portage wants to install eudev. So I simply unmerged udev and 
> installed eudev.

  See https://archives.gentoo.org/gentoo-dev/message/bbd5a2a5775eebbb7e62161125c66135
at the end of a long thread on gentoo-dev...

> The council has approved the following decision 7-0:
> 
> "In light of the support for eudev among Gentoo non-systemd users,
> and a lack of strong technical drivers to block a change, the Council
> approves changing the default virtual/udev provider for non-systemd
> users to eudev. The council encourages all maintainers to try to
> support either provider and cooperate with those who provide patches
> when necessary."
> 
> I'd recommend that the eudev team implement the change and communicate
> vs just having a stampede for the virtual...

  If you are not running systemd, then eudev is the preferred udev
implementation.  Binary distros can build systemd, extract udev on a
developer's machine and package it like a library.  Gentoo, being
source-based, has to do some hackish workarounds, installing, and then
removing, much of systemd on the user's machine with every update to
udev.  Lennart Poettering has made no secret that he's chomping at the
bit to get rid of standalone udev.  Even more ominous is the following

https://lists.freedesktop.org/archives/systemd-devel/2015-May/032147.html

> * A new (currently still internal) API sd-device.h has been
>   added to libsystemd. This modernized API is supposed to
>   replace libudev eventually. In fact, already much of libudev
>   is now just a wrapper around sd-device.h.

-- 
Walter Dnes <waltdnes@waltdnes.org>
I don't run "desktop environments"; I run useful applications

Re: [gentoo-user] Change from udev to eudev?

[wabe]

waltdnes@waltdnes.org wrote:

> On Mon, Jun 13, 2016 at 12:06:18AM +0200, wabe wrote
> > Marc Joliet <marcec@gmx.de> wrote:
> >   
> > > On Wednesday 08 June 2016 02:43:07 wabe wrote:
> > > [...]  
> > > >But I wonder why portage wanna change udev to eudev on my
> > > >system. It seems that this is not the case for everyone else.
> > > >I'm using a stable hardened gentoo system and did not change USE
> > > >flags or other settings. Just started my regular update
> > > >process.    
> > > [...]
> > > 
> > > My suspicion is that libgudev is in @world (or in a set your
> > > created yourself). Perhaps try "emerge --deselect libgudev"; if
> > > it works, the hard blocker should become a soft blocker ("b"
> > > instead of "B"), which portage can resolve by itself.  
> > 
> > It isn't listed in /var/lib/portage/world. But it's a dependency of
> > about a dozen of packages on my system.
> > 
> > At the moment I don't have enough time to search for the reason why 
> > portage wants to install eudev. So I simply unmerged udev and 
> > installed eudev.  
> 
>   See
> https://archives.gentoo.org/gentoo-dev/message/bbd5a2a5775eebbb7e62161125c66135
> at the end of a long thread on gentoo-dev...
> 
> > The council has approved the following decision 7-0:
> > 
> > "In light of the support for eudev among Gentoo non-systemd users,
> > and a lack of strong technical drivers to block a change, the
> > Council approves changing the default virtual/udev provider for
> > non-systemd users to eudev. The council encourages all maintainers
> > to try to support either provider and cooperate with those who
> > provide patches when necessary."
> > 
> > I'd recommend that the eudev team implement the change and
> > communicate vs just having a stampede for the virtual...  

THX a lot for this info. 

>   If you are not running systemd, then eudev is the preferred udev
> implementation.  Binary distros can build systemd, extract udev on a
> developer's machine and package it like a library.  Gentoo, being
> source-based, has to do some hackish workarounds, installing, and then
> removing, much of systemd on the user's machine with every update to
> udev.  Lennart Poettering has made no secret that he's chomping at the
> bit to get rid of standalone udev.  Even more ominous is the following
> 
> https://lists.freedesktop.org/archives/systemd-devel/2015-May/032147.html
> 
> > * A new (currently still internal) API sd-device.h has been
> >   added to libsystemd. This modernized API is supposed to
> >   replace libudev eventually. In fact, already much of libudev
> >   is now just a wrapper around sd-device.h.  
> 

I'm glad that gentoo users still have an alternative to systemd, and 
hope that this will also be the case in future.

But I really don't wanna start another pro/con systemd thread here! ;-)

--
Regards
wabe

[gentoo-user] Re: Change from udev to eudev?

[James]

wabe <wabenbau <at> gmail.com> writes:


> waltdnes <at> waltdnes.org wrote:


> I'm glad that gentoo users still have an alternative to systemd, and
> hope that this will also be the case in future.

Non Systemd has a very bright future. In clustering, Systemd is ok, even
great for containers. In Hi Performance Computing types of clusters, systemd
is loosing the battle. Many in these trenches
believe that the cluster engines of HPC cluster architectures
will vastly outperform clusters with systemd; thus eventually
removing systemd from linux clusters where performance is important.


Still, if you manage 1000 linux workstations, then systemd does have
it's merits.


> But I really don't wanna start another pro/con systemd thread here! ;-)

Exactly. I just wanted to encourage the non-systemd folks that their future
looks very bright.

> Regards
> wabe


hth,
James

Re: [gentoo-user] Re: Change from udev to eudev?

[J. Roeleveld]

On Monday, June 13, 2016 02:10:27 PM James wrote:
> wabe <wabenbau <at> gmail.com> writes:
> Still, if you manage 1000 linux workstations, then systemd does have
> it's merits.

Serious question: What makes systemd more suitable to manage 1000 linux 
workstations when compared to, for instance, OpenRC?

--
Joost

[gentoo-user] Re: Change from udev to eudev?

[James]

J. Roeleveld <joost <at> antarean.org> writes:

> 
> On Monday, June 13, 2016 02:10:27 PM James wrote:
> > wabe <wabenbau <at> gmail.com> writes:
> > Still, if you manage 1000 linux workstations, then systemd does have
> > it's merits.

> Serious question: What makes systemd more suitable to manage 1000 linux 
> workstations when compared to, for instance, OpenRC?

> Joost


Seriously?
(note:: awkward position for me to defend systemd....)


Because RHEL says so? Why else would they promote systemd?

Because It's what bloggers say that make systemd the Kool_aid of choice
these days?

Because really, I was just being polite and trying very hard to say
something nice about systemd?

Because Jim Morrison told me systemd is the way to nirvana, in a 60s laden
pipe dream?

Because, if you are not promoting systemd, you are just not Quool....?

Because, resistance, defined as the counterflow to Systemd flux,
is futile? Reflectance is defined as the summation of your futile resistance
area, under the curve. The endpoint being when you finally addopted
(integrated) systemd into your hopes and dreams?

Because cross-dressing the linux systems you manage, with different, custom
scripts, is so 2010. We all need to wear the emperor's new clothes, to be
hip, just like lennertd ?

Because the NSA is funding systemd, and those that do not cooperate, will be
barred from all GSA  and large corporate contracts?

Because Big, Corporate management believes that systemd will enable them to
replace seasoned linux admins with mindless drones from the labor pool?
(Note::Management is always the first to 'drink the Kool_aide' from other
large, corporate vendors)? You do not want to know what else they do, after
guzzling the kool_aide.....

Because, I think we all know that I'm no whiz at systemd, actually far from
it; in fact I'll be a very late adopter (perhaps post mortem as they inject
me with embedded linux micro-nomes on my way to an oceanic burial)?


So, one of the common arguments you here is that Systemd can standardize
management across different linux distros. If fact many promote systemd
based on a standardization track, as a really good idea. So in a large
installation, it provides the inter-intra-system discipline thereby reducing
the tendency of admins to create fiefdoms (via unique scripts) within the
different machines that different admins manage ( vs traditional divide and
conquer strategies).

Perhaps a workshop or conference is a good idea, should you want the latest,
expert advice on systemd [1]; just pay attention to the "no smoking signs"
posted near the kool_aid punch-bowl. 

(liar liar, hair on fiar)  -- da doors, resurrection tour.


[1] http://0pointer.net/blog/


it's been great fun defending systemd!
James

Re: [gentoo-user] Re: Change from udev to eudev?

[Marc Joliet]

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On Tuesday 14 June 2016 06:46:32 J. Roeleveld wrote:
>On Monday, June 13, 2016 02:10:27 PM James wrote:
>> wabe <wabenbau <at> gmail.com> writes:
>> Still, if you manage 1000 linux workstations, then systemd does have
>> it's merits.
>
>Serious question: What makes systemd more suitable to manage 1000 linux
>workstations when compared to, for instance, OpenRC?
>
>--
>Joost

Well, since nobody else gave a proper response yet...

Not being somebody who manages lots of containers like that, I'm not aware of *all* 
of the relevant features and how they interact, but one that I can think of is that 
systemd can communicate with systemd instances running in containers started with 
systemd-nspawn (e.g., "machinectl status <name>" gives you the status of systemd 
+ services in a container).  In fact, systemd-nspawn could probably be seen as such a 
feature in itself (though personally, when I do use it, it's mainly as chroot on steroids).  
Oh, and its cgroups management probably helps, that is, I *think* that you can limit 
resource consumption of containers that way, just like with service units (though I'm 
not 100% sure of that).

In general, my understanding is that systemd provides base features that container 
management software utilises, and not so much that systemd by itself does container 
management.

Perhaps somebody with more systemd expertise will now feel compelled to respond ;-) 
.

HTH
=2D- 
Marc Joliet
=2D-
"People who think they know everything really annoy those of us who know we
don't" - Bjarne Stroustrup


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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">
<html><head><meta name="qrichtext" content="1" /><style type="text/css">
p, li { white-space: pre-wrap; }
</style></head><body style=" font-family:'DejaVu Sans Mono'; font-size:11pt; font-weight:400; font-style:normal;">
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">On Tuesday 14 June 2016 06:46:32 J. Roeleveld wrote:</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;On Monday, June 13, 2016 02:10:27 PM James wrote:</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;&gt; wabe &lt;wabenbau &lt;at&gt; gmail.com&gt; writes:</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;&gt; Still, if you manage 1000 linux workstations, then systemd does have</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;&gt; it's merits.</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;Serious question: What makes systemd more suitable to manage 1000 linux</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;workstations when compared to, for instance, OpenRC?</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;--</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&gt;Joost</p>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; ">&nbsp;</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">Well, since nobody else gave a proper response yet...</p>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; ">&nbsp;</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">Not being somebody who manages lots of containers like that, I'm not aware of *all* of the relevant features and how they interact, but one that I can think of is that systemd can communicate with systemd instances running in containers started with systemd-nspawn (e.g., &quot;machinectl status &lt;name&gt;&quot; gives you the status of systemd + services in a container).  In fact, systemd-nspawn could probably be seen as such a feature in itself (though personally, when I do use it, it's mainly as chroot on steroids).  Oh, and its cgroups management probably helps, that is, I *think* that you can limit resource consumption of containers that way, just like with service units (though I'm not 100% sure of that).</p>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; ">&nbsp;</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">In general, my understanding is that systemd provides base features that container management software utilises, and not so much that systemd by itself does container management.</p>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; ">&nbsp;</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">Perhaps somebody with more systemd expertise will now feel compelled to respond ;-) .</p>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; ">&nbsp;</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">HTH</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">-- </p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">Marc Joliet</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">--</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">&quot;People who think they know everything really annoy those of us who know we</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">don't&quot; - Bjarne Stroustrup</p>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; ">&nbsp;</p></body></html>
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On Tuesday 14 June 2016 06:46:32 J. Roeleveld wrote:
>On Monday, June 13, 2016 02:10:27 PM James wrote:
>> wabe <wabenbau <at> gmail.com> writes:
>> Still, if you manage 1000 linux workstations, then systemd does have
>> it's merits.
>
>Serious question: What makes systemd more suitable to manage 1000 linux
>workstations when compared to, for instance, OpenRC?
>
>--
>Joost

Well, since nobody else gave a proper response yet...

Not being somebody who manages lots of containers like that, I'm not aware of *all* 
of the relevant features and how they interact, but one that I can think of is that 
systemd can communicate with systemd instances running in containers started with 
systemd-nspawn (e.g., "machinectl status <name>" gives you the status of systemd 
+ services in a container).  In fact, systemd-nspawn could probably be seen as such a 
feature in itself (though personally, when I do use it, it's mainly as chroot on steroids).  
Oh, and its cgroups management probably helps, that is, I *think* that you can limit 
resource consumption of containers that way, just like with service units (though I'm 
not 100% sure of that).

In general, my understanding is that systemd provides base features that container 
management software utilises, and not so much that systemd by itself does container 
management.

Perhaps somebody with more systemd expertise will now feel compelled to respond ;-) 
.

HTH
-- 
Marc Joliet
--
"People who think they know everything really annoy those of us who know we
don't" - Bjarne Stroustrup


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Re: [gentoo-user] Re: Change from udev to eudev?

[Rich Freeman]

On Wed, Jun 15, 2016 at 3:06 AM, Marc Joliet <marcec@gmx.de> wrote:
> Perhaps somebody with more systemd expertise will now feel compelled to
> respond ;-) .

I think I've gotten burned out talking about the advantages of systemd
on Gentoo lists.  If anybody wants to chat about it feel free to ping
me via email or irc, but not in a channel.  Or just ask in any of the
bazillion forums where systemd is the norm.  Or just do a Google
search or search the various list archives.

FWIW, other than Arch you'd be hard-pressed to find a distro that
supports systemd better than Gentoo if you do want to use it...

-- 
Rich

Re: [gentoo-user] Re: Change from udev to eudev?

[Tom H]

On Wed, Jun 15, 2016 at 6:29 AM, Rich Freeman <rich0@gentoo.org> wrote:
>
> I think I've gotten burned out talking about the advantages of systemd
> on Gentoo lists. If anybody wants to chat about it feel free to ping
> me via email or irc, but not in a channel.

You're giving up far too early! There are a few more years of arguing to come ;)

Re: [gentoo-user] Change from udev to eudev?

[waltdnes]

On Tue, Jun 07, 2016 at 05:05:47PM -0500, Dale wrote

> I switched mine back when eudev was new and not even stable yet.  It was
> as simple as unmerge udev and emerge eudev.  I don't recall even doing a
> reboot, which I rarely do here anyway. 

  *** WARNING *** After unmerging udev, do *NOT*, repeat *NOT*, reboot
*** UNTIL AFTER INSTALLING EUDEV *** (same applies to going the other
way).  You cannot boot Gentoo without a device manager in place.  Once
you've installed eudev, you'll get an urgent message to execute...

/etc/init.d/udev --nodeps restart

  At this point, you can safely reboot, but a restart is less of a pain.

-- 
Walter Dnes <waltdnes@waltdnes.org>
I don't run "desktop environments"; I run useful applications

Re: [gentoo-user] Change from udev to eudev?

[Dale]

waltdnes@waltdnes.org wrote:
> On Tue, Jun 07, 2016 at 05:05:47PM -0500, Dale wrote
>
>> I switched mine back when eudev was new and not even stable yet.  It was
>> as simple as unmerge udev and emerge eudev.  I don't recall even doing a
>> reboot, which I rarely do here anyway. 
>   *** WARNING *** After unmerging udev, do *NOT*, repeat *NOT*, reboot
> *** UNTIL AFTER INSTALLING EUDEV *** (same applies to going the other
> way).  You cannot boot Gentoo without a device manager in place.  Once
> you've installed eudev, you'll get an urgent message to execute...
>
> /etc/init.d/udev --nodeps restart
>
>   At this point, you can safely reboot, but a restart is less of a pain.
>


That is a good point to make.  The best way to be sure, emerge -C udev
&& emerge eudev and don't do anything until at least that finishes. 
Rebooting in the middle would be bad. 

Can a system even boot without udev?  I would think the bootloader would
get it to a certain point but then die later on.  :/

Dale

:-)  :-) 

Re: [gentoo-user] Change from udev to eudev?

[karl]

Dale:
...
> Can a system even boot without udev?

Yes, use sys-fs/static-dev (unless you have some special boot 
requirements).

>  I would think the bootloader would get it to a certain point
> but then die later on.  :/

The bootloader needs to find the kernel and possible the initrd/
initramfs if you use them.

Then kernel needs (depending on your setup) to find the root
filesystem and then /sbin/init.

And init needs to start up the rest of the system.

The above have been working wery well for a long time, but if you don't
use udev and initrd et al, most (all?) distributions don't help you
anymore with it; you have to know yourself how to do it.

Regards,
/Karl Hammar

-----------------------------------------------------------------------
Aspö Data
Lilla Aspö 148
S-742 94 Östhammar
Sweden
+46 173 140 57

Re: [gentoo-user] Change from udev to eudev?

[Dale]

karl@aspodata.se wrote:
> Dale:
> ...
>> Can a system even boot without udev?
> Yes, use sys-fs/static-dev (unless you have some special boot 
> requirements).

Well, I was talking about if udev was removed and then a reboot was
done.  I would think it would boot to a certain point then when whatever
started and needed devices to be created in /dev, it would start
failing.  I suspect this would vary depending on the install as well. 


>
>>  I would think the bootloader would get it to a certain point
>> but then die later on.  :/
> The bootloader needs to find the kernel and possible the initrd/
> initramfs if you use them.
>
> Then kernel needs (depending on your setup) to find the root
> filesystem and then /sbin/init.
>
> And init needs to start up the rest of the system.
>
> The above have been working wery well for a long time, but if you don't
> use udev and initrd et al, most (all?) distributions don't help you
> anymore with it; you have to know yourself how to do it.
>
> Regards,
> /Karl Hammar
>
> -----------------------------------------------------------------------
> Aspö Data
> Lilla Aspö 148
> S-742 94 Östhammar
> Sweden
> +46 173 140 57
>

I get what you are saying and sounds about right. I figure the
bootloader would load the kernel and the kernel would do most of the
loading until it needed something that udev does.  At that point, things
start to fail.  I'm not going to test this theory tho.  ;-)

Dale

:-)  :-) 

Re: [gentoo-user] Change from udev to eudev?

[waltdnes]

On Thu, Jun 09, 2016 at 08:16:57AM -0500, Dale wrote
> karl@aspodata.se wrote:
> > Dale:
> > ...
> >> Can a system even boot without udev?
> > Yes, use sys-fs/static-dev (unless you have some special boot 
> > requirements).
> 
> Well, I was talking about if udev was removed and then a reboot
> was done.  I would think it would boot to a certain point then when
> whatever started and needed devices to be created in /dev, it would
> start failing.  I suspect this would vary depending on the install
> as well.

  You need *A* device-manager.  You can use udev, eudev, static-dev,
mdev, whatever, but you need something.  Mind you, some software assumes
or requires udev/eudev.

-- 
Walter Dnes <waltdnes@waltdnes.org>
I don't run "desktop environments"; I run useful applications

Re: [gentoo-user] Change from udev to eudev?

[Dale]

waltdnes@waltdnes.org wrote:
> On Thu, Jun 09, 2016 at 08:16:57AM -0500, Dale wrote
>> karl@aspodata.se wrote:
>>> Dale:
>>> ...
>>>> Can a system even boot without udev?
>>> Yes, use sys-fs/static-dev (unless you have some special boot 
>>> requirements).
>> Well, I was talking about if udev was removed and then a reboot
>> was done.  I would think it would boot to a certain point then when
>> whatever started and needed devices to be created in /dev, it would
>> start failing.  I suspect this would vary depending on the install
>> as well.
>   You need *A* device-manager.  You can use udev, eudev, static-dev,
> mdev, whatever, but you need something.  Mind you, some software assumes
> or requires udev/eudev.
>


What I was referring to was if during this switch from udev to eudev,
someone rebooted without any dev manager at all.  In other words, emerge
-C udev and then reboot before emerging eudev or some other dev
manager.  I suspect that would get interesting pretty quick. 

Dale

:-)  :-) 

[gentoo-user] Re: Change from udev to eudev?

[Jonathan Callen]

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On 06/09/2016 10:00 AM, Dale wrote:
> waltdnes@waltdnes.org wrote:
>> On Thu, Jun 09, 2016 at 08:16:57AM -0500, Dale wrote
>>> karl@aspodata.se wrote:
>>>> Dale:
>>>> ...
>>>>> Can a system even boot without udev?
>>>> Yes, use sys-fs/static-dev (unless you have some special boot 
>>>> requirements).
>>> Well, I was talking about if udev was removed and then a reboot
>>> was done.  I would think it would boot to a certain point then when
>>> whatever started and needed devices to be created in /dev, it would
>>> start failing.  I suspect this would vary depending on the install
>>> as well.
>>   You need *A* device-manager.  You can use udev, eudev, static-dev,
>> mdev, whatever, but you need something.  Mind you, some software assumes
>> or requires udev/eudev.
>>
> 
> 
> What I was referring to was if during this switch from udev to eudev,
> someone rebooted without any dev manager at all.  In other words, emerge
> -C udev and then reboot before emerging eudev or some other dev
> manager.  I suspect that would get interesting pretty quick. 
> 
> Dale
> 
> :-)  :-) 
> 
> 

Actually, you no longer need a user-space device manager at all, unless
you want to be able to access device nodes under /dev as a user that
isn't UID=0 or has CAP_DAC_OVERRIDE.  The kernel provides a devtmpfs
filesystem that will have every single device node that udev used to
create (udev no longer even creates the devices -- it just relies on
devtmpfs doing so), but most of them will be owned by 0:0 (root:root)
with permissions 0600; excepting certain nodes like /dev/null or
/dev/zero, which will be owned by 0:0 with permissions 0666.  One other
thing that udev does that you might rely on is to create symlinks like
/dev/disk/by-label/*, which can be used by mount(8) if you specify
LABEL=foo in /etc/fstab.  The only other things that I'm aware of udev
doing is to rename network devices and (possibly) to notify other
applications of changes, somehow (but I'm not sure that it actually does
that).

If you don't actually need any of that (you are working on an embedded
system where you only need root anyway, for instance), then you can just
use a bare devtmpfs without a device manager changing permissions,
adding links, etc.

-- 
Jonathan Callen


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Re: [gentoo-user] Re: Change from udev to eudev?

[Dale]

Jonathan Callen wrote:
> On 06/09/2016 10:00 AM, Dale wrote:
>> waltdnes@waltdnes.org wrote:
>>> On Thu, Jun 09, 2016 at 08:16:57AM -0500, Dale wrote
>>>> karl@aspodata.se wrote:
>>>>> Dale:
>>>>> ...
>>>>>> Can a system even boot without udev?
>>>>> Yes, use sys-fs/static-dev (unless you have some special boot 
>>>>> requirements).
>>>> Well, I was talking about if udev was removed and then a reboot
>>>> was done.  I would think it would boot to a certain point then when
>>>> whatever started and needed devices to be created in /dev, it would
>>>> start failing.  I suspect this would vary depending on the install
>>>> as well.
>>>   You need *A* device-manager.  You can use udev, eudev, static-dev,
>>> mdev, whatever, but you need something.  Mind you, some software assumes
>>> or requires udev/eudev.
>>>
>>
>> What I was referring to was if during this switch from udev to eudev,
>> someone rebooted without any dev manager at all.  In other words, emerge
>> -C udev and then reboot before emerging eudev or some other dev
>> manager.  I suspect that would get interesting pretty quick. 
>>
>> Dale
>>
>> :-)  :-) 
>>
>>
> Actually, you no longer need a user-space device manager at all, unless
> you want to be able to access device nodes under /dev as a user that
> isn't UID=0 or has CAP_DAC_OVERRIDE.  The kernel provides a devtmpfs
> filesystem that will have every single device node that udev used to
> create (udev no longer even creates the devices -- it just relies on
> devtmpfs doing so), but most of them will be owned by 0:0 (root:root)
> with permissions 0600; excepting certain nodes like /dev/null or
> /dev/zero, which will be owned by 0:0 with permissions 0666.  One other
> thing that udev does that you might rely on is to create symlinks like
> /dev/disk/by-label/*, which can be used by mount(8) if you specify
> LABEL=foo in /etc/fstab.  The only other things that I'm aware of udev
> doing is to rename network devices and (possibly) to notify other
> applications of changes, somehow (but I'm not sure that it actually does
> that).
>
> If you don't actually need any of that (you are working on an embedded
> system where you only need root anyway, for instance), then you can just
> use a bare devtmpfs without a device manager changing permissions,
> adding links, etc.
>


That's interesting to read.  I recall reading about the devtmpfs in the
kernel but thought that was for just the very early stages of booting,
reading /boot to get the kernel and such things required to start the
boot process.  I figured once it got started, it would eventually get to
a point and sort of hang up because it couldn't find devices to read to
keep going. 

Interesting.  Still don't want to test the theory tho.  ;-) 

Dale

:-)  :-) 

Re: [gentoo-user] Re: Change from udev to eudev?

[waltdnes]

On Thu, Jun 09, 2016 at 10:18:01PM -0400, Jonathan Callen wrote

> Actually, you no longer need a user-space device manager at all, unless
> you want to be able to access device nodes under /dev as a user that
> isn't UID=0 or has CAP_DAC_OVERRIDE.  The kernel provides a devtmpfs
> filesystem that will have every single device node that udev used to
> create (udev no longer even creates the devices -- it just relies on
> devtmpfs doing so), but most of them will be owned by 0:0 (root:root)
> with permissions 0600; excepting certain nodes like /dev/null or
> /dev/zero, which will be owned by 0:0 with permissions 0666.  One other
> thing that udev does that you might rely on is to create symlinks like
> /dev/disk/by-label/*, which can be used by mount(8) if you specify
> LABEL=foo in /etc/fstab.  The only other things that I'm aware of udev
> doing is to rename network devices and (possibly) to notify other
> applications of changes, somehow (but I'm not sure that it actually does
> that).
> 
> If you don't actually need any of that (you are working on an embedded
> system where you only need root anyway, for instance), then you can just
> use a bare devtmpfs without a device manager changing permissions,
> adding links, etc.

  Interesting.  In the initial panic after the announcement that udev
would be subsumed by systemd, I started what went on to become the
Gentoo wiki entries at...

 https://wiki.gentoo.org/wiki/Mdev
 https://wiki.gentoo.org/wiki/Mdev/Automount_USB
 https://wiki.gentoo.org/wiki/Mdev/Automount_USB/automount

  I wonder if it would be possible to set up a functional multi-user
devtempfs-based system with appropriate permissions being granted in
/etc/sudoers.d/  It would certainly be an interesting project.

-- 
Walter Dnes <waltdnes@waltdnes.org>
I don't run "desktop environments"; I run useful applications

Re: [gentoo-user] Re: Change from udev to eudev?

[wabe]

Jonathan Callen <jcallen@gentoo.org> wrote:

> On 06/09/2016 10:00 AM, Dale wrote:
> > waltdnes@waltdnes.org wrote:  
> >> On Thu, Jun 09, 2016 at 08:16:57AM -0500, Dale wrote  
> >>> karl@aspodata.se wrote:  
> >>>> Dale:
> >>>> ...  
> >>>>> Can a system even boot without udev?  
> >>>> Yes, use sys-fs/static-dev (unless you have some special boot 
> >>>> requirements).  
> >>> Well, I was talking about if udev was removed and then a reboot
> >>> was done.  I would think it would boot to a certain point then
> >>> when whatever started and needed devices to be created in /dev,
> >>> it would start failing.  I suspect this would vary depending on
> >>> the install as well.  
> >>   You need *A* device-manager.  You can use udev, eudev,
> >> static-dev, mdev, whatever, but you need something.  Mind you,
> >> some software assumes or requires udev/eudev.
> >>  
> > 
> > 
> > What I was referring to was if during this switch from udev to
> > eudev, someone rebooted without any dev manager at all.  In other
> > words, emerge -C udev and then reboot before emerging eudev or some
> > other dev manager.  I suspect that would get interesting pretty
> > quick. 
> > 
> > Dale
> > 
> > :-)  :-) 
> > 
> >   
> 
> Actually, you no longer need a user-space device manager at all,
> unless you want to be able to access device nodes under /dev as a
> user that isn't UID=0 or has CAP_DAC_OVERRIDE.  The kernel provides a
> devtmpfs filesystem that will have every single device node that udev
> used to create (udev no longer even creates the devices -- it just
> relies on devtmpfs doing so), but most of them will be owned by 0:0
> (root:root) with permissions 0600; excepting certain nodes
> like /dev/null or /dev/zero, which will be owned by 0:0 with
> permissions 0666.  One other thing that udev does that you might rely
> on is to create symlinks like /dev/disk/by-label/*, which can be used
> by mount(8) if you specify LABEL=foo in /etc/fstab.  The only other
> things that I'm aware of udev doing is to rename network devices and
> (possibly) to notify other applications of changes, somehow (but I'm
> not sure that it actually does that).
> 
> If you don't actually need any of that (you are working on an embedded
> system where you only need root anyway, for instance), then you can
> just use a bare devtmpfs without a device manager changing
> permissions, adding links, etc.

THX for all the information. Now I understand better what (e)udev is
doing.

--
Regards
wabe