What Is Nested Virtualization?

Nested Virtualization is a feature that allows you to run a virtual machine within a virtual machine while still using hardware acceleration from the host machine. Put simply, it allows you to run a vm inside of a vm.

Enabling Nested Virtualization In Proxmox

Everything we do will be done on the host system running Proxmox. Once enabled, the guest can take advantage of it.

First we need to check to see if nested virtualization is enabled in Proxmox.

If you’re running an Intel CPU run this command:

cat /sys/module/kvm_intel/parameters/nested

If you’re running an AMD CPU run this command:

cat /sys/module/kvm_amd/parameters/nested

You should see an output of Y or N. If N this means that nested virtualization is not enabled, so let’s enabled it!

On the Proxmox host, run the following command as root:

If you’re running an Intel CPU run this command:

echo "options kvm-intel nested=Y" > /etc/modprobe.d/kvm-intel.conf

If you’re running an AMD CPU run this command:

echo "options kvm-amd nested=1" > /etc/modprobe.d/kvm-amd.conf 

Next reboot the system

reboot

Then check to see if nexted virtualization is enabled on the Proxmox host:

If you’re running an Intel CPU run this command:

cat /sys/module/kvm_intel/parameters/nested

If you’re running an AMD CPU run this command:

cat /sys/module/kvm_amd/parameters/nested

You should see Y this time. This means that you can now using virtulization inside of a VM, just be sure to set your VM’s processor accordingly! (use HOST for CPU type)