Nested KVM2013/10/22

	Configure nested KVM. It's possible to install KVM and create virtual machines as nested KVM on KVM host.
[1]	The Kernel of CentOS 6 is 2.6.32 and it does not support Nested KVM, so it's necessarry to update to supported Kernel for Nested KVM first.

[root@dlp ~]#

yum -y install centos-release-xen

[root@dlp ~]#

sed -i -e "s/enabled=1/enabled=0/g" /etc/yum.repos.d/CentOS-Xen.repo

[root@dlp ~]#

yum --enablerepo=Xen4CentOS -y update kernel

[root@dlp ~]#

vi /boot/grub/grub.conf

# add at the end of the line of kernel like follows

kernel /vmlinuz-3.4.61-9.el6.centos.alt.x86_64 ro root=/dev/mapper/VolGroup-lv_root
rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD rd_LVM_LV=VolGroup/lv_swap SYSFONT=latarcyrheb-sun16
crashkernel=auto console=ttyS0,115200n8 rd_LVM_LV=VolGroup/lv_root
KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM

kvm-intel.nested=1

[root@dlp ~]#

reboot

# confirm status ( it's OK if it is "Y" )

[root@dlp ~]#

cat /sys/module/kvm_intel/parameters/nested

[2]	Make sure the CPU model on your computer.

[root@dlp ~]#

virsh capabilities | egrep "/model|/vendor"

<model>SandyBridge</model>

# CPU Model

<vendor>Intel</vendor>

# CPU Vendor

[3]	Edit the configuration of a virtual machine you'd like to nest like follows. It's OK to configure nested KVM and you can create virtual machines on the virtual machine nested.

[root@dlp ~]#

virsh edit www

# edit a virtual machine "www"

# add following lines

# CPU model

<model fallback='allow'>SandyBridge</model>

# CPU vendor

<vendor>Intel</vendor>
<feature policy='require' name='vmx'/>
</cpu>

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