Open Stack

Hey folks,

Before we bump the agreed upon[1] minimum versions for libvirt and QEMU
for 'Stein', we need to do the tedious work of picking the NEXT_MIN_*
versions for the 'T' (which is still in the naming phase) release, which
will come out in the autumn (Sep-Nov) of 2019.

Proposal
--------

Looking at the DistroSupportMatrix[2], it seems like we can pick the
libvirt and QEMU versions supported by the next LTS release of Ubuntu --
18.04; "Bionic", which are:

    libvirt: 4.0.0
    QEMU:    2.11

Debian, Fedora, Ubuntu (Bionic), openSUSE currently already ship the
above versions.  And it seems reasonable to assume that the enterprise
distribtions will also ship the said versions pretty soon; but let's
double-confirm below.

Considerations and open questions
---------------------------------

(a) KVM for IBM z Systems: John Garbutt pointed out[3] on IRC that:
    "IBM announced that KVM for IBM z will be withdrawn, effective March
    31, 2018 [...] development will not only continue unaffected, but
    the options for users grow, especially with the recent addition of
    SuSE to the existing support in Ubuntu."

    The message seems to be: "use a regular distribution".  So this is
    covered, if we a version based on other distributions.

(b) Oracle Linux: Can you please confirm if you'll be able to
    release libvirt and QEMU to 4.0.0 and 2.11, respectively?

(c) SLES: Same question as above.

Assuming Oracle Linux and SLES confirm, please let us know if there are
any objections if we pick NEXT_MIN_* versions for the OpenStack 'T'
release to be libvirt: 4.0.0 and QEMU: 2.11.

    * * *

A refresher on libvirt and QEMU release schedules
-------------------------------------------------

  - There will be at least 12 libvirt releases (_excluding_ maintenance
    releases) by Autumn 2019.  A new libvirt release comes out every
    month[4].

  - And there will be about 4 releases of QEMU.  A new QEMU release
    comes out once every four months.

[1] http://git.openstack.org/cgit/openstack/nova/commit/?h=master&id=28d337b
    -- Pick next minimum libvirt / QEMU versions for "Stein"
[2] https://wiki.openstack.org/wiki/LibvirtDistroSupportMatrix
[3] http://kvmonz.blogspot.com/2017/03/kvm-for-ibm-z-withdrawal.html
[4] https://libvirt.org/downloads.html#schedule

-- 
/kashyap