Eric Blake <eblake@redhat.com> writes:
On 07/30/2012 12:00 PM, Mauricio Tavares wrote:
On Mon, Jul 30, 2012 at 1:50 PM, Eric Blake <eblake@redhat.com> wrote:
On 07/15/2012 07:52 PM, Mauricio Tavares wrote:
Right on the top of http://www.centos.org/docs/5/html/5.2/Virtualization/chap-Virtualization-Man..., it seems to imply you can load/send scripts to the vm guest using virsh. Is that possible? How and what are the limitations? Can you query the vm guest?
What type of scripts are you talking about? You may be thinking more about the capabilities of what libguestfs provides, for modifying disk images. In general, virsh itself controls how to start a guest, but not the additional layers of communication (such as virtio, qemu-ga, or the libguestfs appliance app) required for a host to command a guest to do something from within the guest.
Basic one would be in case a machine has been paused for a long time. You know as in "hey, you lazy vm! You have been sleeping for two weeks! Now your clock is way off and poor ntp can't sync it back. So, here's current date!"
That is something that fits better through qemu-ga, but no one has implemented it yet (cc'ing qemu-devel in case I'm misrepresenting things). Of course, if we did have a qemu-ga command for pushing the current time into the guest, then libvirt could usefully expose an API to wrap that qemu-ga command.
Could you setup a wiki page on qemu.org with a list of qemu-ga commands that libvirt would like? Adding commands is pretty trivial so if ya'll have a list of things you'd like, they're great quick tasks that we can find folks to work on. Regards, Anthony Liguori
-- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org