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On 04/04/2018 10:45 AM, Kashyap Chamarthy wrote:
> Answering my own questions about Debian --
> 
> From looking at the Debian Archive[1][2], these are the versions for
> 'Stretch' (the current stable release) and in the upcoming 'Buster'
> release:
> 
>     libvirt | 3.0.0-4+deb9u2         | stretch
>     libvirt | 4.1.0-2                | buster
> 
>     qemu    | 1:2.8+dfsg-6+deb9u3    | stretch
>     qemu    | 1:2.11+dfsg-1          | buster
> 
> I also talked on #debian-backports IRC channel on OFTC network, where I
> asked: 
> 
>     "What I'm essentially looking for is: "How can 'stretch' users get
>     libvirt 3.2.0 and QEMU 2.9.0, even if via a different repository.
>     As they are proposed to be least common denominator versions across
>     distributions."
> 
> And two people said: Then the versions from 'Buster' could be backported
> to 'stretch-backports'.  The process for that is to: "ask the maintainer
> of those package and Cc to the backports mailing list."
> 
> Any takers?
> 
> [0] https://packages.debian.org/stretch-backports/
> [1] https://qa.debian.org/madison.php?package=libvirt
> [2] https://qa.debian.org/madison.php?package=qemu

Hi Kashyap,

Thanks for your considering of Debian, asking me and giving enough time
for answering! Here's my thoughts.

I updated the wiki page as you suggested [1]. As i wrote on IRC, we
don't need to care about Jessie, so I removed Jessie, and added Buster/SID.

tl;dr: just skip this section & go to conclusion

backport of libvirt/QEMU/libguestfs more in details
---------------------------------------------------

I already attempted the backports from Debian Buster to Stretch.

All of the 3 components (libvirt, qemu & libguestfs) could be built
without extra dependency, which is a very good thing.

- libvirt 4.1.0 compiled without issue, though the dh_install phase
failed with this error:

dh_install: Cannot find (any matches for) "/usr/lib/*/wireshark/" (tried
in "." and "debian/tmp")
dh_install: libvirt-wireshark missing files: /usr/lib/*/wireshark/
dh_install: missing files, aborting

Without more investigation but this build log, it's likely a minor fix
in debian/*.install files to make it possible to backport the package.

- qemu 2.11 built perfectly with zero change.

- libguestfs 1.36.13 only needed to have fdisk replaced by util-linux as
build-depends (fdisk is now a separate package in Buster).

So it looks like easy to backport these 3 *AT THIS TIME*. [2]

However, without a cristal ball, nobody can tell how hard it will be to
backport these *IN A YEAR FROM NOW*.

Conclusion:
-----------

If you don't absolutely need new features from libvirt 3.2.0 and 3.0.0
is fine, please choose 3.0.0 as minimum.

If you don't absolutely need new features from qemu 2.9.0 and 2.8.0 is
fine, please choose 2.8.0 as minimum.

If you don't absolutely need new features from libguestfs 1.36 and 1.34
is fine, please choose 1.34 as minimum.

If you do need these new features, I'll do my best adapt. :)

About Buster freeze & OpenStack Stein backports to Debian Stretch
-----------------------------------------------------------------

Now, about Buster. As you know, Debian doesn't have planned release
dates. Though here's the stats showing that roughly, there's a new
Debian every 2 years, and the freeze takes about 6 months.

https://wiki.debian.org/DebianReleases#Release_statistics

With this logic and considering Stretch was released last year in June,
after Stein is released, Buster will probably start its freeze. If the
Debian freeze happens later, good for me, I'll have more time to make
Stein better. But then Debian users will probably expect an OpenStack
Stein backport to Debian Stretch, and that's where it can become tricky
to backport these 3 packages.

The end
-------

I hope the above isn't too long, and helps to take the best decision,
Cheers,

Thomas Goirand (zigo)

[1]
https://wiki.openstack.org/wiki/LibvirtDistroSupportMatrix#Distro_minimum_versions

[2] I'm not shouting, just highlighting the important part! :)