Enable Nested Virtualization in Proxmox Virtual Machine

Nested virtualization allows you to run other hypervisors in a virtual machine. In this article, we will look at how to enable nested virtualization in Proxmox VE for Intel and AMD processors.

Check the processor model on the Proxmox host:

$ lscpu | egrep --color -i "Vendor ID|Model name"

Depending on the processor model, check if nested virtualization is enabled in Proxmox:

For Intel processors:

$ cat /sys/module/kvm_intel/parameters/nested

For AMD CPUs:

$ cat /sys/module/kvm_intel/parameters/nested

If you see Y or 1, nested virtualization is supported. If N or 0, then no.

To enable nested KVM virtualization for Intel processors:

$ sudo modprobe -r kvm_intel
$ sudo modprobe kvm_intel nested=1
$ sudo echo "options kvm-intel nested=Y" > /etc/modprobe.d/kvm-intel.conf
$ sudo modprobe -r kvm_intel
$ sudo modprobe kvm_intel

For AMD processors:

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

Now you need to enable nested virtualization support for the Proxmox virtual machine:

$ qm set <ID> --cpu host

In this case, the VM CPU type will change to host.

Note. For AMD processors, you need to add additional parameters to the VM configuration file:args: -cpu host,+svm

Turn off and turn on the VM. Check if the guest OS now supports virtualization. Connect to the VM console (Ubuntu in this example) and run the command:

$ egrep --color -i "svm|vmx" /proc/cpuinfo