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<div class="moz-cite-prefix">Waiting Daniel's reply, but afaik, the
new NBD server is available since qemu-1.4 and libvirt 1.0.2<br>
Daniel, feel free to confirm or blame me.<br>
<br>
Btw, kvm capabilities are available in upstream qemu since
qemu-1.3 which works like a charm with Nova (Folsom).<br>
-Sylvain<br>
<br>
Le 24/04/2013 23:23, Lorin Hochstein a écrit :<br>
</div>
<blockquote
cite="mid:CADzpNMXMJizb=dMvhTQz=5WabRyaLe4E5HkMno6x-rVZs1ODGA@mail.gmail.com"
type="cite">
<div dir="ltr"><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed, Apr 24, 2013 at 11:59 AM,
Daniel P. Berrange <span dir="ltr"><<a
moz-do-not-send="true" href="mailto:dan@berrange.com"
target="_blank">dan@berrange.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="">
<div class="h5">On Wed, Apr 24, 2013 at 11:48:35AM
-0400, Lorin Hochstein wrote:<br>
> In the docs, we describe how to configure KVM
block-based live migration,<br>
> and it has the advantage of avoiding the need for
shared storage of<br>
> instances.<br>
><br>
> However, there's this email from Daniel Berrangé
from back in Aug 2012:<br>
> <a moz-do-not-send="true"
href="http://osdir.com/ml/openstack-cloud-computing/2012-08/msg00293.html"
target="_blank">http://osdir.com/ml/openstack-cloud-computing/2012-08/msg00293.html</a><br>
><br>
> "Block migration is a part of the KVM that none
of the upstream developers<br>
> really like, is not entirely reliable, and most
distros typically do not<br>
> want to support it due to its poor design (eg not
supported in RHEL).<br>
><br>
> It is quite likely that it will be removed in
favour of an alternative<br>
> implementation. What that alternative impl will
be, and when I will<br>
> arrive, I can't say right now."<br>
><br>
> Based on this info, the OpenStack Ops guide
currently recommends against<br>
> using block-based live migration, but the Compute
Admin guide has no<br>
> warnings about this.<br>
><br>
> I wanted to sanity-check against the mailing list
to verify that this was<br>
> still the case. What's the state of block-based
live migration with KVM?<br>
> Should we say be dissuading people from using it,
or is it reasonable for<br>
> people to use it?<br>
<br>
</div>
</div>
What I wrote above about the existing impl is still
accurate. The new<br>
block migration code is now merged into libvirt and makes
use of an<br>
NBD server built-in to the QMEU process todo block
migration. API<br>
wise it should actually work in the same way as the
existing deprecated<br>
block migration code. So if you have new enough libvirt
and new enough<br>
KVM, it probably ought to 'just work' with openstack
without needing<br>
any code changes in nova. I have not actually tested this
myself<br>
though.<br>
<br>
So we can probably update the docs - but we'd want to
checkout just<br>
what precise versions of libvirt + qemu are needed, and
have someone<br>
check that it does in fact work.<br>
<br>
</blockquote>
<div><br>
</div>
<div style="">Thanks, Daniel. I can update the docs
accordingly. How can I find out what are the minimum
versions of libvirt and qemu are needed? </div>
<div style=""><br>
</div>
<div style="">Also, I noticed you said "qemu" and not "kvm",
and I see that <a moz-do-not-send="true"
href="http://wiki.qemu.org/KVM">http://wiki.qemu.org/KVM</a>
says that qemu-kvm fork for x86 is "deprecated, use
upstream QEMU now". Is it the case now that when using
KVM as the hypervisor for a host, an admin will just
install a "qemu" package instead of a "qemu-kvm" package
to get the userspace stuff?</div>
<div style=""><br>
</div>
<div style="">Lorin</div>
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