OpenStack Compute (Nova)

Libvirt/KVM virtio (paravirtualisation)

Asked by Édouard Thuleau on 2011-08-08

Is it possible to disable virtio driver when we use Libvirt/KVM virt driver ?
In my case, I need to use old guest host with linux kernel under 2.6.25 and it cannot boot with virtio driver (cannot mount fielsystem). And I think, we will meet the same problem with windows VM.

Question information

Language:
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Status:
Solved
For:
OpenStack Compute (nova) Edit question
Assignee:
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Solved by:
Vish Ishaya
Solved:
2011-08-10
Last query:
2011-08-10
Last reply:
2011-08-09
Brian Lamar (blamar) said : #1

Can you provide a dump of the XML from a VM which isn't working for you? The libvirt.xml.template should provide you the ability to modify which drivers get loaded in your VMs, but it's not perfect and doesn't handle all situations currently. Also, relevant errors via paste.openstack.org or screenshots will help for quicker debugging if you can provide more information, thanks!

Vish Ishaya (vishvananda) said : #2

sure you can switch the libvirt.xml to attach drives via scsi or ide instead, if you don't mind the performance penalty.

You can't disable them per instance at the moment though, it is all or nothing.

On Aug 8, 2011, at 3:26 AM, Edouard Thuleau wrote:

> New question #167302 on OpenStack Compute (nova):
> https://answers.launchpad.net/nova/+question/167302
>
> Is it possible to disable virtio driver when we use Libvirt/KVM virt driver ?
> In my case, I need to use old guest host with linux kernel under 2.6.25 and it cannot boot with virtio driver (cannot mount fielsystem). And I think, we will meet the same problem with windows VM.
>
> --
> You received this question notification because you are a member of Nova
> Core, which is an answer contact for OpenStack Compute (nova).

Édouard Thuleau (ethuleau) said : #3

@Vish: Ok thanks.

Another question, why the virtio driver isn't enabled for the network device ? It's commented in the libvirt XML template.

Best Vish Ishaya (vishvananda) said : #4

See the linked FAQ:
FAQ #1734: “Why doesn't nova use virtio networking by default?”.

Édouard Thuleau (ethuleau) said : #5

Ok thanks.

Édouard Thuleau (ethuleau) said : #6

Thanks Vish Ishaya, that solved my question.