Re: [Libvir] Guest Identification
On Fri, Aug 11, 2006 at 09:05:12AM -0400, Daniel Veillard wrote:
On Thu, Aug 10, 2006 at 04:28:20PM -0400, Juan Walker wrote:
> On 8/10/06, Daniel Veillard <veillard(a)redhat.com> wrote:
> > Domains have an unique identifier which you can extract:
> > http://libvirt.org/html/libvirt-libvirt.html#virDomainGetUUID
>
>
> Ah, great! Thanks. Is it possible for me to find out the UUID from something
> running on domU? I need to have the application connect to the server and
> identify the information it's sending as being from its specific domain. Any
> ideas?
Oh, I don't think domU has access to that information, libvirt is meant to be
used on dom0, won't work in domU.
Yeah it is not a job for libvirt, but you can get this info within DomU if you
are using recent enough Xen tools (xen-unstable / forthcoming Xen 3.0.3)
In fully-virt (HVM) guests you can query the SMBIOS for it using DMIDecode.
# dmidecode | grep --after 7 'Handle 0x0001'
Handle 0x0001
DMI type 1, 25 bytes.
System Information
Manufacturer: IBM
Product Name: 2672JHG
Version: ThinkPad X31
Serial Number: KBPKNB2
UUID: EF861801-45B9-11CB-88E3-AFBFE5370493
Incidentally if you want a sensible UUID for Domain0 rather than the one Xen
gives (0000000-00000-0000-0000-000000) then you can again use DMIDecode to
get the UUID associated with the physical machine - this example above is from
my laptop in Domain-0.
On para-virt guests you can get the UUID from a file in sysfs:
/sys/hypervisor/uuid
As I say above though both of these tricks require a fairly recent set of
Xen tools from xen-unstable. Failing that you could do some tricks such as
passing the UUID on the kernel boot command line when starting the DomU
instance and then access that from /proc/cmdline.
Regards,
Dan.
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