KVM nested virtualization

kvm_nested_virtualization.txt

L0 = bare metal machine
L1 = VM on bare metal
L2 = VM on VM

First, ensure virtualization is enabled on L0 as described here: https://docs.fedoraproject.org/en-US/quick-docs/using-nested-virtualization-in-kvm/#proc_enabling-nested-virtualization-in-kvm

Next, launch L1 with the following Vagrant config (or an equivalent directly on the hypervisor):

Vagrant.configure("2") do |config|
  config.vm.box = "generic/ubuntu1604"
  config.vm.provider :libvirt do |libvirt|
    libvirt.cpus = 4
    libvirt.memory = 16000
    libvirt.nested = true
    libvirt.cpu_mode = "host-passthrough"
    libvirt.driver = "kvm"
  end
end

Finally, launch L2 from within L1 using the following Vagrant config:

Vagrant.configure("2") do |config|
  config.vm.box = "fedora/28-cloud-base"
  config.vm.provider :libvirt do |libvirt|
    libvirt.cpus = 1
    libvirt.memory = 1000
    libvirt.driver = "kvm"
    libvirt.management_network_name = 'vagrant-libvirt-new'
    libvirt.management_network_address = '192.168.124.0/24'
  end
end

Installing vagrant and libvirt on the L1

sudo apt-get update -y
sudo apt-get install -y libvirt-bin libvirt-dev qemu-utils qemu wget
sudo /etc/init.d/libvirt-bin restart
sudo addgroup libvirtd
sudo usermod -a -G libvirtd $USER


wget https://releases.hashicorp.com/vagrant/2.2.4/vagrant_2.2.4_x86_64.deb
sudo dpkg -i vagrant_2.2.4_x86_64.deb

vagrant plugin install vagrant-libvirt
vagrant plugin install vagrant-mutate