# Install vagrant-libvirt

    sudo apt-get install libxslt-dev libxml2-dev libvirt-dev qemu-utils
    vagrant plugin install vagrant-libvirt
    vagrant plugin install vagrant-mutate

# convert kvm box to libvirt box

    vagrant mutate trusty64 libvirt

# Config Vagrantfile

    Vagrant.configure('2') do |config|
      config.vm.box = "trusty64"
  
      config.vm.define :control do |control|
        control.vm.hostname = "controller"
        control.vm.network :public_network
        control.vm.network :private_network, ip: "192.168.123.10"
        control.vm.provider :kvm do |kvm, override|
          kvm.memory_size     = '2048m'
        end
        control.vm.provider :libvirt do |libvirt, override|
          libvirt.memory = 2048
          libvirt.nested = true
        end
      end

      config.vm.define :network do |network|
        network.vm.hostname = "network"
        network.vm.network :public_network
        network.vm.network :private_network, ip: "192.168.123.12"
        network.vm.provider :kvm do |kvm, override|
          kvm.memory_size     = '2048m'
        end
        network.vm.provider :libvirt do |libvirt, override|
          libvirt.memory = 2048
          libvirt.nested = true
        end
      end

    end

# Vagrant up and access

     vagrant up --provider=libvirt
     vagrant ssh control
     vagrant ssh network