What's this /run directory doing on my system and where does it come from?

[Bryn M. Reeves]

On 03/30/2011 01:11 PM, Ralf Corsepius wrote:
> On 03/30/2011 02:10 PM, Michał Piotrowski wrote:
>> 2011/3/30 Ralf Corsepius<rc040203 at freenet.de>:
>>> On 03/30/2011 01:54 PM, Lennart Poettering wrote:
>>>> Heya,
>>>>
>>>> I just uploaded a new version of systemd into F15, which establishes a
>>>> directory /run in the root directory. Most likely you'll sooner or later
>>>> stumble over it, so here's an explanation what this is and why this is.
>>>>
>>>> It's a fairly minor technical change,
>>> It's a massive FHS violation
>> FHS has 7 years, must be updated.
>>
>>> =>  release blocker.
>> Flame! :D
> No, it's a no-go/no-way in most verbose form.
> 

If strict FHS compliance was a release criteria it's hard to see how we'd have
made it to F15 in the first place.

I also don't think you can really justify the "massive" qualifier in your
assertion. The actual text of the (7 year old) FHS has this to say:

"Applications must never create or require special files or subdirectories in
the root directory. Other locations in the FHS hierarchy provide more than
enough flexibility for any package.

     Rationale
     There are several reasons why creating a new subdirectory of the root
     filesystem is prohibited:
     • It demands space on a root partition which the system administrator may
       want kept small and simple for either performance or security reasons.
     • It evades whatever discipline the system administrator may have set up
       for distributing standard file hierarchies across mountable volumes.

Distributions should not create new directories in the root hierarchy
without extremely careful consideration of the consequences including for
application portability."

I'll agree that the standard's wording isn't as clear as it might be (don't you
just love 'em?) but the last paragraph certainly seems to allow distributions to
add subdirectories to the root directory with "extremely careful consideration
of the consequences".

I find it interesting that you consider a breach of the "root directory
pollution rule" sufficiently serious to be a release blocker and yet you have
apparently remained silent as all the abuses of the /dev directory that Lennart
pointed out were merged in previous releases.

Why is that those FHS violations are OK but adding a directory to / (in an
obvious effort to address one of the shortcomings of the existing standard) is
the end of the world as we know it?

No standard is or even should be carved in stone for all eternity.

Regards,
Bryn.