[Users] nested KVM
Nathanaël Blanchet
blanchet at abes.fr
Wed Oct 3 10:25:06 UTC 2012
Hi,
Thanks for your answer. everything is all right now, I've managed to
resolve the issue thanks to your suggestion.
This is what I've done:
1. I recall that my processor is a Westmere one
2. first on the hypervisor :
[root at node ~]# qemu-kvm -version
QEMU emulator version 1.0.1 (qemu-kvm-devel), Copyright (c)
2003-2008 Fabrice Bellard
this qemu-kvm release is the one from the F17 update repository
3. still on the hypervisor
[root at node ~]# qemu-kvm -cpu ?
x86 Opteron_G3
x86 Opteron_G2
x86 Opteron_G1
x86 SandyBridge
x86 Nehalem
x86 Penryn
x86 Conroe
x86 [n270]
x86 [athlon]
x86 [pentium3]
x86 [pentium2]
x86 [pentium]
x86 [486]
x86 [coreduo]
x86 [kvm32]
x86 [qemu32]
x86 [kvm64]
x86 [core2duo]
x86 [phenom]
x86 [qemu64]
So we can see there that no Westmere or neither Opteron_G4 is
supported by 1.0.1 qemu-kvm. the consequence is this message on the
hypervisor logs : "Preferred CPU model Westmere not allowed by
hypervisor; closest supported model will be used"
4. when doing "ps aux | grep enable-kvm", we see the -cpu flag being
kvm64, a generic kvm processor. But none of the proposed item into
the "CPU name" cluster field matches with "kvm64", that's the reason
why it's impossible there to run a nested KVM. A kvm64 item should
successfully launch the vm, but it will never be implemented into
the ovirt webadmin because nested KVM is only for testing purpose
(and vm performances are very bad !)
5. So what doing when we have a Westmere processor type and a F17 so as
to successfully run a nested kvm???? upgrading to qemu 1.2 thanks to
the virt preview repository
(http://fedoraproject.org/wiki/Virtualization_Preview_Repository)
now running qemu-kvm -cpu ? gives :
[root at node ~]# qemu-kvm -cpu ?
x86 Opteron_G4
x86 Opteron_G3
x86 Opteron_G2
x86 Opteron_G1
x86 SandyBridge
x86 Westmere
x86 Nehalem
x86 Penryn
x86 Conroe
x86 [n270]
x86 [athlon]
x86 [pentium3]
x86 [pentium2]
x86 [pentium]
x86 [486]
x86 [coreduo]
x86 [kvm32]
x86 [qemu32]
x86 [kvm64]
x86 [core2duo]
x86 [phenom]
x86 [qemu64]
Now when running the hypervisor with the Westmere cpu flag is
successfull and the kvm64 flag is not used anymore. Then, chosing
the Westmere Family into the CPU family cluster field will launch
the nested vm with the right Westmere flag !
Obviously, qemu-kvm 1.2 will be included by default into F18 and all of
this will be deprecated but waiting for, upgrading the qemu version can
be very useful having a running test environnment with many virtual
hypervisor when the hardware is a Wetmere family one.
Le 26/09/2012 04:06, Mark Wu a écrit :
> On 09/26/2012 12:58 AM, Nathanaël Blanchet wrote:
>> Hello,
>>
>> I've tried many times to run a node as a guest in ovirt following
>> http://wiki.ovirt.org/wiki/Vdsm_Developers#Running_Node_as_guest_-_Nested_KVM
>> . The result is that I'm able to register such a host in engine, but
>> it is impossible to start any vm on it. If I boot on an ISO, I can
>> see the first prompt and move between the items. But since I begin
>> the installation I have a blank screen and the vm goes into pause
>> mode in vit-manager. Then I have no way else than rebooting the
>> hypervisor guest because it is impossible to resume. When I get logs
>> on the real host, I can find this :
>> arning : x86Decode:1306 : Preferred CPU model Westmere not allowed by
>> hypervisor; closest supported model will be used
>> Sep 25 17:11:59 khamsin libvirtd[23053]: 2012-09-25
>> 15:11:59.384+0000: 23054: warning : x86Decode:1306 : Preferred CPU
>> model Westmere not allowed by hypervisor; closest supported model
>> will be used
>> Sep 25 17:12:19 khamsin libvirtd[23053]: 2012-09-25
>> 15:12:19.150+0000: 23055: warning : x86Decode:1306 : Preferred CPU
>> model Westmere not allowed by hypervisor; closest supported model
>> will be used
>> Sep 25 17:45:48 khamsin libvirtd[23053]: 2012-09-25
>> 15:45:48.342+0000: 23058: warning : x86Decode:1306 : Preferred CPU
>> model Westmere not allowed by hypervisor; closest supported model
>> will be used
>> Sep 25 18:07:05 khamsin libvirtd[23053]: 2012-09-25
>> 16:07:05.834+0000: 23058: warning : x86Decode:1306 : Preferred CPU
>> model Nehalem not allowed by hypervisor; closest supported model will
>> be used
>> Sep 25 18:44:47 khamsin libvirtd[23053]: 2012-09-25
>> 16:44:47.340+0000: 23057: warning : x86Decode:1306 : Preferred CPU
>> model Penryn not allowed by hypervisor; closest supported model will
>> be used
>>
>> As you can see, I have tried many cpu type for launching this guest
>> hypervisor, but none of them is accepted by the hypervisor. Plus,
>> I've modified each time the family type in the cluster tab, but it is
>> the same.
>> On the hist:
>> #virsh capabilities gives
>> <cpu>
>> <arch>x86_64</arch>
>> <model>Westmere</model>
>> <vendor>Intel</vendor>
>>
>> Thanks for your help
>
>
> What does the command 'qemu-kvm -cpu ?' give ? Could you please try
> the following guest cpu definition?
> *
> <cpu match='exact'>
> <model>core2duo</model>
> <feature policy='require' name='vmx'/>
> </cpu>
>
>
> *
--
Nathanaël Blanchet
Supervision réseau
Pôle exploitation et maintenance
Département des systèmes d'information
227 avenue Professeur-Jean-Louis-Viala
34193 MONTPELLIER CEDEX 5
Tél. 33 (0)4 67 54 84 55
Fax 33 (0)4 67 54 84 14
blanchet at abes.fr
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