Re: [gentoo-dev] rfc: locations of binaries and separate /usr

[Thomas Sachau]

William Hubbs schrieb:
> On Tue, Jan 03, 2012 at 10:22:15PM +0100, Fabian Groffen wrote:
>>> I'll have to go through on my system at
>>> least and find all of the ebuilds that install things in
>>> /{bin,sbin,lib}. I'll open a tracker bug as soon as udev-176  is
>>> released; this will list all of the things we need to do to complete the
>>> migration.
>>
>> I would suggest not to do this.  It's more interesting to know what udev
>> really requires to be in /usr/bin.
>
> The issues involve binaries in /{bin,sbin} that link to libraries in
> /usr/lib as well as packages that install udev rules that run binaries.
>
>>
>>> Basically I have these in my head:
>>>
>>> * mask udev-176 in the tree.
>>> * figure out and document how to make a simple initramfs with dracut.
>>> * unmask udev 176 making sure to point users with a separate /usr
>>>   partition to how to make an initramfs (I could probably do this with
>>>   ewarns in the ebuild and maybe a news item before we go stable).
>>>   * stabilize a version of dracut.
>>> * stabilize >=udev-176 and kmod.
>
> The part of the process above is the part I am the most concerned about.
> I think we need to get everyone who is using separate /usr switched over
> to an initramfs with udev 176, and this needs to happen sooner than
> later, without using things like wrapper scripts or ways to avoid the
> initramfs. Those are just stop-gap options that will only work until
> some package they are depending on migrates to /usr.
>
> Once we get to this point in the process, I think we could take each
> package that installs things in / individually and migrate it. But, I
> think the part of the process listed above needs to happen sooner than
> later.
>
> What are your thoughts?
>
> William
>

If i did not miss something in this long thread, we are currently mostly
talking about udev needing /usr to be mounted when it starts. Systemd is
not our default init system and other packages are currently not
changing their default. Since udev is our default and that requires a
mounted /usr, we should show our users their options with a suggested
default:

1. minimal initramfs (default suggestion)
2. switching from udev to mdev (avoids required /usr of udev)
3. some wrapper script to mount /usr before udev starts

for 1: I use myself a self-created initramfs, which has worked fine for
many kernel releases, the only adjustment needed was back with kernel
2.6.27. With this in mind, some default minimal initramfs should be
doable without much maintaincence work.

for 2: from what i did read up to now, this option looks interesting for
those people, who dont want to use an initramfs or other mounting script
and dont use advanced features of udev, so especially server setups or
minimal desktop systems



For the idea of complete migration to /usr, i see no reason to go this
route in advance. Just keep with our default install locations and
follow upstream, if and where needed.
If a package switches to /usr and depending packages follow, fine, let
them do that and we can follow without much additional work.
There is no need to do such migration beforehand or changing our install
location in advance.


So in short:

1. Tell our users about the change in udev and show them their options
with a suggested default one.
2. for the rest, just calm down, follow upstreams and only change the
install location where needed. No need for mental pressure without an
actual pressure. ;-)

-- 

Thomas Sachau
Gentoo Linux Developer