[libvirt] [virt-tools-list] Tracking VM installations

Richard W.M. Jones rjones at redhat.com
Thu Jul 5 07:54:20 UTC 2012

On Thu, Jul 05, 2012 at 04:49:49AM +0300, Zeeshan Ali (Khattak) wrote:
> On Thu, Jul 5, 2012 at 12:09 AM, Richard W.M. Jones <rjones at redhat.com> wrote:
> > You can use libguestfs (specifically, virt-df) to display the amount
> > of disk space used in the guest.
> For target disk, we use libvirt's storage volume API and that provides
> us API to get current allocation.

libvirt storage API gives you a different number (blocks allocated) so
it won't work for VMs backed with LVs or preallocated files.  virt-df
looks inside the filesystem(s).  However a guest agent will give you
the most accurate figures when the guest is running, and I imagine a
guest agent may even be able to query the installer somehow.

> > Finally I've always thought it would be a good idea if guests
> > communicated information down to the host about progress, whether that
> > is progress booting or progress installing.  There is (on PC hardware)
> > even an I/O port reserved for this purpose (port 0x80)!  You'd have to
> > get buy-in and get it upstream in qemu and every installer out there.
> > http://stackoverflow.com/questions/6793899/what-does-the-0x80-port-address-connects/6796109#6796109
> That would indeed be awesome but it seems way too much work and fight
> (not to mention, its impossible to fix this in proprietary OSs if they
> don't already support this) for just one progress bar.

I wouldn't necessarily discount this one.  It's a standard of sorts,
and useful in other scenarios that we very much care about,
eg. getting a libvirt event when a guest has started booting, finished
booting, is ready for login, etc.


Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
New in Fedora 11: Fedora Windows cross-compiler. Compile Windows
programs, test, and build Windows installers. Over 70 libraries supprt'd
http://fedoraproject.org/wiki/MinGW http://www.annexia.org/fedora_mingw

More information about the libvir-list mailing list