[libvirt-users] Associating a statefile with an image

[Eric Blake]

On 08/02/2011 07:06 PM, sethuraman subbiah wrote:
>>
>
> I tried changing the disk image and it works fine. But if I try to change
> the mac address , I get error: unsupported configuration.

That's correct - changing the MAC address would be a guest-visible 
change, with possibly fatal consequences to a guest (your hardware 
doesn't change MAC addresses on the fly, so why should your virtual 
hardware allow it?).

> My aim was to
> perform cloning and change the mac of the cloned image and also doing some
> changes inside the vm to make sure it obtains a new ip. Is there a
> possibility to get this working with the current API ?

Cloning is not a trivial operation.  There is no support for cloning a 
running machine; it is only safe to clone offline disk images, at which 
point, you _can_ modify MAC addresses for the clone, since a guest 
booting with a new MAC address is no different than swapping out 
hardware while your machine was offline.  Virt-manager is able to do 
cloning, and it involves multiple libvirt API calls; perhaps studying 
that source will give you some better ideas.  It is unlikely that 
libvirt will ever be able to support cloning in a single API call; 
rather it will continue to support enough API to be used in sequence to 
do a clone.  Likewise, cloning a live machine (even one whose state was 
saved by 'virsh save' or 'virsh snapshot') is unlikely to ever be possible.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org