Is possible to enable virtio-RNG or other entropy system?

I am trying to install to install freeipa in a centos 7 image, this software makes heavy use of entropy, because it’s configure and use kerberos… I’ve been looking a solution on google and i found the virtio-rng qemu support. Is there any way to use it or another system to emulate entropy in the guests?

You can add features not supported by OpenNebula using the RAW parameter. For your case to add the virtio rgn example from libvirt documentation you can use this RAW parameter in the VM template:

  <rng model='virtio'>
    <rate period="2000" bytes="1234"/>
    <backend model='random'>/dev/random</backend>