Running a virtual machine within a virtual machine (aka nested virtual machines) is supported by OpenStack by adding a stanza such as
<cpu mode='custom' match='exact'>
<model>Nehalem</model>
<feature policy='require' name='vmx'/>
</cpu>
in the libvirt.xml.template file. The nested feature must be enabled on the OpenStack node for intel processors by adding the nested=1 argument when loading the kvm_intel module so that:
# cat /sys/module/kvm_intel/parameters/nested Y
This feature can be used to exercise an automated Openstack deployement on Debian GNU/Linux wheezy with razor within OpenStack itself.
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