libvirt users - May 2010 - Qemu driver not supporting VIR_DOMAIN_DEVICE_MODIFY_CONFIG yet?

Hi,

According to the docs on
http://libvirt.org/html/libvirt-libvirt.html#virDomainDetachDeviceFlags
I ought to be able to do

virDomainDetachDeviceFlags(
	<domain>,
	<devicexml>,
	VIR_DOMAIN_DEVICE_MODIFY_LIVE | VIR_DOMAIN_DEVICE_MODIFY_CONFIG);

to detach a volume both from a currently running VM instance and permanently 
from the defined config file.

If I actually try that, though, I'm getting this error:

libvir: QEMU error : Requested operation is not valid: cannot modify the 
persistent configuration of a domain

The same thing happens whether or not the domain is running and also happens 
if I leave out the "VIR_DOMAIN_DEVICE_MODIFY_LIVE" part.

Does the qemu driver simply not support VIR_DOMAIN_DEVICE_MODIFY_CONFIG yet 
(libvirt 0.8.1), or is there some other problem here?

	Guido

On 05/31/2010 11:52 AM, Guido Winkelmann wrote:
> Hi,
> 
> According to the docs on
> http://libvirt.org/html/libvirt-libvirt.html#virDomainDetachDeviceFlags
> I ought to be able to do
> 
> virDomainDetachDeviceFlags(
> 	<domain>,
> 	<devicexml>,
> 	VIR_DOMAIN_DEVICE_MODIFY_LIVE | VIR_DOMAIN_DEVICE_MODIFY_CONFIG);
> 
> to detach a volume both from a currently running VM instance and
permanently
> from the defined config file.
> 
> If I actually try that, though, I'm getting this error:
> 
> libvir: QEMU error : Requested operation is not valid: cannot modify the 
> persistent configuration of a domain
> 
> The same thing happens whether or not the domain is running and also
happens
> if I leave out the "VIR_DOMAIN_DEVICE_MODIFY_LIVE" part.
> 
> Does the qemu driver simply not support VIR_DOMAIN_DEVICE_MODIFY_CONFIG yet
> (libvirt 0.8.1), or is there some other problem here?
> 
Sounds like you are doing things right, this just isn't implemented for
the qemu driver yet. To make a persistent change, you will have to edit
the domain XML, remove the device, and redefine the domain.

- Cole