OpenStack Compute (nova)

Expose root disk bus as a setting in nova boot

Asked by Rob

Hi folks,

Nova seems to be hamstrung when it comes to older versions of Linux or Windows. For example, if I alter:

https://github.com/openstack/nova/blob/master/nova/virt/libvirt/connection.py#L1516

to use "ide" instead, I can now start Windows 2000/XP & older linux kernel instances. Unfortunately I lose the advantages of virtio block devices in newer OS'.

I was wondering if it would make sense to expose this as a setting somewhere. If so, what shape would that take? I was thinking a parameter to nova boot would be perfect, but I don't have the perspective to tell if that makes sense. Would love to hear opinions.

Thanks.

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Vish Ishaya (vishvananda) said : 		#1

We discussed using image_metadata for this. As in if the image metadata says that the instance supports virtio, use it, otherwise fall back to ide or iscsi.

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Rob (pjriot+openstack) said : 		#2

Thanks Vish,

Can you give any details on the implementation? Mainly when you expect it to be worked on? Is there an open bug id? I wouldn't mind lending a hand.

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Vish Ishaya (vishvananda) said : 		#3

There was a brief comment about something similar for networks here. I can't find an open bug about volumes:

https://bugs.launchpad.net/nova/+bug/702040

I think we had a blueprint about it but it probably got removed in the last big blueprint cleanup. I don't think anyone is actively working on it, so if you would like to tackle it that would be awesome.

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João Soares (joaosoares) said : 		#4

Hi,

I am having a problem related to this! I can boot my instance using virt-manager and setting Disk bus to IDE, but on OpenStack it fails to deploy since it set ths Disk bus to Virto.

Are there any developments on this matter?

Best Regards,
João

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Rob (pjriot+openstack) said : 		#5

Hi Joao,

Vish got back to me via email regarding their ideas for implementation:

We discussed using image_metadata for this. As in if the image metadata says that the instance supports virtio, use it, otherwise fall back to ide or iscsi.

I fully intended to follow up but I've been distracted since. I can't commit to it any time soon either I'm afraid. I'm hoping to get back to my openstack project in the new year. I'll try to get to this then, but no promises.

Can you help with this problem?

Provide an answer of your own, or ask Rob for more information if necessary.

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