Libvirt image based provisioning without backing volume

Hi Guys,

I know that Foreman is using fog to create new VMs in Libvirt. In fog, in general, there is a possibility to create VM without backing volume if we have prepared an image. Unfortunately in Foreman, I can’t find a way how to do it and if I understand code in good way this is impossible. Is this true? Maybe there is some path to create a new VM based on an image without backing volume, just using provided image by itself.
Until implementation of Foreman I was doing it with virt-install command like this:
virt-install --memory={0} --vcpus={1} --import --name {2} --disk path=/var/lib/libvirt/images/{2},format=qcow2 --os-type=linux --os-variant=rhel7 --network bridge=br0 --autostart --graphics none --virt-type kvm --console pty,target_type=virtio".format(memory, cpus, node)

I don’t think it’s possible. Patches welcome.