Enable Nested Virtualization on Proxmox
VMs with nesting active (vmx/svm flag) cannot be live-migrated! To be done on the physical PVE host (or any other hypervisor).
To enable nested hardware-assisted virtualization:
- Ensure you have an AMD CPU or a very recent Intel one.
- Ensure your kernel version is >= 3.10 (usually the case after Proxmox VE 4.x).
- Enable nested support.
Step-by-Step Guide
Check Nested Virtualization Status
To check if nested virtualization is enabled:
cat /sys/module/kvm_intel/parameters/nestedNIf it shows "N", it means it's not enabled. To activate it for Intel CPUs:
echo "options kvm-intel nested=Y" > /etc/modprobe.d/kvm-intel.confFor AMD CPUs:
echo "options kvm-amd nested=1" > /etc/modprobe.d/kvm-amd.confReboot or reload the kernel module:
modprobe -r kvm_intel
modprobe kvm_intelCheck again:
cat /sys/module/kvm_intel/parameters/nestedYNote: Pay attention to the use of dash "-" and underscore "_" in the module names.
Configure Virtual Machine
Then, create a guest where you install, for example, Proxmox as nested Virtualization Environment. Set the CPU type to "host":
qm set <vmid> --cpu hostVerify Nested Virtualization
Once the guest OS is installed, if it's GNU/Linux, you can enter and verify that hardware virtualization support is enabled by doing:
egrep '(vmx|svm)' --color=always /proc/cpuinfoConclusion
That's it! You've enabled nested hardware-assisted virtualization.
Happy virtualizing!