On Fri, Aug 3, 2012 at 9:49 AM, Eric Blake <eblake@redhat.com> wrote:

[please don't top-post on technical lists]

On 08/03/2012 09:02 AM, Harish Patil wrote:
> Thanks Michal.
> Yes I do not have a screen, the host and the guests are running on an
> embedded device.
> The real requirement is:
> Is there a way that I can register with libvirt for the state change
> notifications in the guest OS?
> Is it possible?
> I need to take some actions in the host based on the guest OS state change.

How would you do this in a network of bare metal machines? You may be
better served by setting up actions based on network messages sent by
the guest, the way you would with one bare-metal machine reporting to
another. Also, this sounds more like something that a guest agent would
have to coordinate at a higher level than libvirt, as there is nothing
inherent in running qemu that tells libvirt what the guest inside the
qemu process is doing. virt-dmesg' ability to peek at guest memory is
about the best you will be able to do through libvirt.

>>

Thanks Eric. Understand that there is no such facility at the libvirt level. Do you know whether such notification can be received/trapped at the qemu level itself ? I had once checked that QEVENT_RESET event is emitted when the guest OS reboots.

>> 1: http://people.redhat.com/~rjones/virt-dmesg/

--
Eric Blake eblake@redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org