UsrMove feature (was Re: FESCo meeting minutes for 2011-10-24)

[Harald Hoyer]

On 10/24/2011 08:05 PM, Chris Adams wrote:
>> ===================================
>> #fedora-meeting: FESCO (2011-10-24)
>> ===================================
>>    * Discussion about https://fedoraproject.org/wiki/Features/UsrMove
>>      (t8m, 17:26:45)
>
> This sounds interesting (speaking as an admin that typically sets up
> servers with separate, ro-mounted, /usr).  I'm not sure about moving
> _everything_ to /usr, but I guess that's one approach.  Other Unix
> systems I've used have had /bin as a symlink to /usr/bin, but not /sbin
> (still kept core system maintenance tools in /sbin on root fs).  I'm
> also not sold on eliminating sbin directories (I like having "system
> admin" type stuff kept separate), and I don't see why that needs to be
> rolled into the same feature (especially as just a footnote, not a
> top-line change).

What does it gain to have /sbin and /usr/sbin? Security through 
obscurity? We already have it in $PATH for the normal user.

>
> One big question though: can RPM handle such a change?  IIRC, when the
> switch from /etc/rc.d/init.d to /etc/init.d was made, initially
> everything was going to be moved and the old paths symlinked for a few
> releases.  However, there was some problem with RPM that couldn't handle
> switching an existing directory to a symlink, so that change was reduced
> to introducing /etc/init.d as a symlink.  How will upgrades be handled
> if this feature goes through?
>

The old symlinks will likely stay forever for scripting compat issues 
and linux loader ABI.

The transition from directory to symlink is to be discussed though.
It can be done from the initramfs, or it can be done from anaconda, or 
it can be done from a %post script with lua in the "filesystem" rpm.