[Buildroot] systemd: write-up and packaging questions

[Arnout Vandecappelle]

On 17/10/14 12:07, Maxime Hadjinlian wrote:
> Hello Hiram, all
> 
> On Fri, Oct 17, 2014 at 10:21 AM, Paassen, Hiram van
> <Hiram.van.Paassen at mastervolt.com> wrote:
>> On zo, 2014-10-12 at 21:12 +0200, Maxime Hadjinlian wrote:
>>>   Hi André, All
>>>
>>> On Sun, Oct 12, 2014 at 7:59 PM, André Erdmann <dywi at mailerd.de> wrote:
[snip]
>>>> Installation
>>>> ------------
>>>>
>>>> systemd's libdir is /lib/system.
>>>> Most unit files (.service et al) are installed to /etc/systemd/system,
>>>> systemd's own unit files are installed to /lib/systemd/system and some
>>>> packages(*) install their files to /usr/lib/systemd/system, which is rather
>>>> confusing. Either dir works (search order is /etc > /lib > /usr/lib),
>>>> but what's the recommended location?
>>> If I'm reading the FHS correctly, /usr/lib/systemd/ would the the
>>> targets and what nots for systemd itself, and so everything in /etc is
>>> hosts specific so I would keep everything installed by our packages in
>>> /etc/systemd/system.
>> I think this depends on your viewpoint:
>> /usr/lib is for "distros" since you might say that buildroot is
>> generating a custom distro I would say that one might want to
>> use /usr/lib
>>
>> This keeps /etc/ for making persistent changes based on individual
>> systems and /run/ for making non persistent changes
>>
>> systemd itself mostly uses /lib
>>
>> Also:
>> See my other mail about systemctl for an hour ago (was unaware of this
>> discussion) The script I'm referring to, taken from open-embedded
>> uses /etc to install symlinks to.
>> So open-embedded seems to have chosen /etc for enable-symlinks
>> independent of where the original unit files are installed (as per
>> systemctl behavior I suppose)
> It usually what is done, yes. You get the symlinks in /etc and you
> install your unit files and targets, where you feel they should be.
> Debian has the symlinks in /etc and the files in /lib/systemd/system/
> I would say that we should follow what the major distribution are
> doing. I assume they already had discussion on how to organize theses
> files.

 FYI, what I learned at ELC-E is that systemd is moving towards being able to
boot with a completely empty /etc. This will allow /etc to be a tmpfs in itself,
or if some configuration needs to be persistent it can be a writable fs and you
can do a factory reset by wiping it. There is some support in the latest systemd
to copy in a skeleton /etc when /etc is empty.

 So with this in mind, a systemd setup would put as little as possible in /etc.


 Regards,
 Arnout


[snip]


-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
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