[Qemu-devel] converging around a single guest agent

[Daniel P. Berrange]

On Tue, Nov 15, 2011 at 05:01:00PM -0600, Michael Roth wrote:
> On 11/15/2011 11:24 AM, Barak Azulay wrote:
> >Hi,
> >
> >One of the breakout sessions during the ovirt workshop [1] was about the guest
> >tools, and focused mainly on the ovirt-guest-agent [2].
> >
> >One of the issues discussed there, was the various existing guest agents out
> >there, and the need to converge the efforts to a single agent that will serve
> >all.
> >
> >while 4 agents were mentioned (Matahari, vdagent, qemu-ga&  ovirt-guest-agent)
> >during that discussion, we narrowed it down to 2 candidates:
> >
> >qemu-ga (aka virt-agent):
> >-------------------------
> >- Qemu specific - it was aimed for specific qemu needs (mainly quiesce guest
> >I/O)
> >- Communicates directly with qemu  (not implemented yet)
> 
> Won't be implemented until we finish the QMP conversion to QAPI
> since that's a prereq to implementing a QMP server with proper async
> support (needed for communication with a potentially non-responsive
> guest agent). But once it's in guest extensions are completely
> transparent to QMP/libvirt, which is highly desirable from a
> management perspective since you're coding against a single
> API/transport.

FYI, I already have patches for libvirt to make it directly talk
to a QEMU guest agent for a guest. We just configure the guest
agent with a UNIX socket on the host, and livirt talks QMP to
that directly. It was trivial, since the agent uses the same
basic protocol as the QMP monitor, so from that POV I really like
the QEMU guest agent for libvirt integration, and loathe to have
to integrate with something that has invented yet another comms
protocol. I expect we'll merge these patches in libvirt 0.9.8
and my intent is for Fedora 17 guests to have qemu-ga installed
by default, so we get reliable guest shutdown/reboot support at
last.

 https://www.redhat.com/archives/libvir-list/2011-October/msg00135.html

Regards,
Daniel
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