[Fedora-packaging] SCL discussion at yesterday's meeting, easy stuff

[Toshio Kuratomi]

On Tue, Nov 05, 2013 at 04:34:47PM +0100, Honza Horak wrote:
> On 11/01/2013 08:28 PM, Toshio Kuratomi wrote:
> >A straw poll was taken about the filesystem location of SCLs.  A few FPC
> >members were willing to use /opt but others were heavily opposed to it.
> >Everyone was okay with using /usr/scl (or the plural form /usr/scls).  So
> >I think that needs to become the scl root dir (is that the right term?) for
> >Fedora.
> >
> >FPC was okay with the idea that third parties might use /usr/scl as well.
> >I didn't bring this up at the meeting but one thing that influences me on
> >this is that scls are inherently rpm managed and therefore mixing both our
> >scls with third party scls does not seem like the same vendor-OS problem
> >that /opt was designed to fix.
> 
> I feel the need to add my POV about choosing /usr/scl for SCL prefix.
> FHS states: "/usr is the second major section of the filesystem. /usr
> is shareable, read-only data. That means that /usr should be
> shareable between various FHS-compliant hosts and must not be written
> to. Any information that is host-specific or varies with time is
> stored elsewhere." [1]
> 
> That seems to me like a no-go for having /usr/scl as a prefix for
> SCLs, because there surely are packages that need to write some
> files, probably not only databases. So I'd also vote for /opt since
> there are no such requirements.
> 
> [1] http://www.pathname.com/fhs/pub/fhs-2.3.html#THEUSRHIERARCHY
>
Although I favor /opt, this is not one of the reasons.  Our interpretation
of /opt is that we also cannot depend on it being read-write and
host-specific.  It looks like fhs developed /opt to be a vendor-friendly
version of /usr.  Therefore it is also read-only and shareable.  The
reasoning stems from FHS's decision to separate read-write and host-specific
information from /opt:

"""
Package files that are variable (change in normal operation) must be
installed in /var/opt. See the section on /var/opt for more information.

Host-specific configuration files must be installed in /etc/opt. See the
section on /etc for more information.
"""

http://www.pathname.com/fhs/pub/fhs-2.3.html#OPTADDONAPPLICATIONSOFTWAREPACKAGES

As stated in my Filesystem Location Part 2 email:
https://lists.fedoraproject.org/pipermail/packaging/2013-November/009717.html

"we also noted that no matter whether /usr or /opt was used, config files
would still need to be placed somewhere under /etc and state files somewhere
under /var."

-Toshio
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: not available
URL: <http://lists.fedoraproject.org/pipermail/packaging/attachments/20131105/bf84d54c/attachment.sig>