Open Stack

Daniel P. Berrange wrote:
> On Fri, Jun 22, 2012 at 12:17:11AM +0800, Huang Zhiteng wrote:
>   
>> Of course it is possible.  What kind of issue did you run into?
>>
>> On Thu, Jun 21, 2012 at 5:52 PM, Wang Li <foxban at gmail.com> wrote:
>>     
>>> hi,all
>>>
>>> I need to run virtual machines on Xen Hypervisor in HVM mode,
>>> is it possible when using libvirt?
>>>       
>
> Actually, this is not currently possible. For reasons I don't
> know, the libvirt driver currently hardcodes use of paravirtualized
> guests when connected to Xen hosts. It does not allow use of HVM
> guests.  There's no particularly good technical reason why it can't
> be made to work.

Right.  I've been working on this in my few spare cycles and hope to
post some patches soon.

>  There'd need to be a way to tag instance types
> with HVM vs paravirt, in addition to their architecture.

I was hoping to just use the vm_mode image property that the XenServer
folks use.  See option 2 in this mail

https://lists.launchpad.net/openstack/msg11507.html

>  The
> libvirt driver would have to expose whether each host supports
> paravirt or HVM or both. The schedular would then have to take
> this into account when placing guests.
>   

I posted an RFC patch here that filters hosts based on the vm_mode image
property and the additional_compute_capabilities flag.  I haven't
received any comments, so should probably just push this to gerrit.

Regards,
Jim