Amazon Web Services (AWS) is expanding EC2 capabilities by supporting nested virtualization on select instance types. These are the C8i, M8i, and R8i instances. They enable organizations to run virtual machines within a virtual machine.
According to The Register, this technology is particularly relevant for scenarios in which entire IT environments need to be simulated or tested. In such cases, the environment often consists of multiple interdependent virtual systems. Nested virtualization can also play a role in modern container platforms, for example when orchestration and management layers need to remain separate from the underlying workloads.
AWS notes that the functionality can be used for software emulation, automotive simulations, and development environments that run Linux on Windows, among other applications. Until now, nested virtualization within AWS has been limited in practice to bare-metal instances, where customers have direct access to the physical hardware. With the new support, this limitation has been partially removed.
The new capabilities are linked to the use of Intel Xeon 6 processors. This generation includes improvements in hardware isolation that better separate virtual environments. Like other EC2 instances, these variants run on AWS Nitro, which handles the abstraction and allocation of hardware resources.
Architecture with multiple virtualization layers
For nested virtualization, Nitro passes certain processor functions to the customer’s virtual machine. This allows the machine to act as a host for an additional virtualization layer. AWS uses a multi-layer model in which the physical infrastructure, the customer hypervisor, and the virtual machines running on top of it are clearly separated.
Currently, customers can choose Hyper-V or KVM as the hypervisor within the EC2 instance. VMware ESXi is not explicitly mentioned as a supported option. This is striking, because ESXi still plays a dominant role in many business environments. However, VMware’s current licensing structure, since its acquisition by Broadcom, makes broad support within public clouds less obvious.
With this expansion, AWS is bringing its offering more in line with other major cloud providers. Microsoft and Google have been offering support for nested virtualization for some time, albeit with their own limitations. AWS is now adding the functionality on a limited number of platforms, taking a first step toward broader deployability.