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virtualization type in /etc/nova/nova.conf

asked 2017-02-02 10:13:47 -0500

Gimaey gravatar image

Hi all,

I'm following the official documentation to install openstack newton on centos 7, however, when configuring virt_type in /etc/nova/nova.conf, the documentation says:

Determine whether your compute node supports hardware acceleration for virtual machines:

$ egrep -c '(vmx|svm)' /proc/cpuinfo If this command returns a value of one or greater, your compute node supports hardware acceleration which typically requires no additional configuration.

If this command returns a value of zero, your compute node does not support hardware acceleration and you must configure libvirt to use QEMU instead of KVM.

What I can't get is how if my node doesn't support hardware acceleration then I'm supposed to use qemu instead of kvm despite the fact that kvm is accelerating agent that is used alongside qemu?

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Which CPU you have installed on the board ?
Have your BIOS settings "Enable VT-X support ?
What is current output lsmod | grep kvm been run by root ?

dbaxps gravatar imagedbaxps ( 2017-02-02 10:40:32 -0500 )edit

Enabling kvm acceleration will update qemu process (cmd) matching particular VM Guest. It requires CPU >= E(XXX) Core2Duo and BIOS supporting VT-X CPU's feature.

dbaxps gravatar imagedbaxps ( 2017-02-02 10:44:28 -0500 )edit

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answered 2017-02-02 20:41:14 -0500

updated 2017-02-02 20:43:42 -0500

qemu is a CPU emulator and doesn't feature HW acceleration out of the box. HW acceleration is achieved by a kernel module named KVM and, I think, some modification of qemu.

In nova.conf, "qemu" is short for "qemu without HW acceleration", "kvm" means "qemu with HW acceleration thanks to KVM". See also

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Asked: 2017-02-02 10:13:47 -0500

Seen: 466 times

Last updated: Feb 02 '17