AWS Enables Nested Virtualization for Enhanced EC2 Instance Flexibility

Amazon Web Services (AWS) has expanded nested virtualization capabilities to its C8i, M8i, and R8i EC2 instances, allowing users to run a hypervisor within a virtual machine. This feature, previously available on bare metal instances, provides a flexible environment for testing, simulation, and containerized workloads.

What is Nested Virtualization?

Nested virtualization involves running a hypervisor inside another hypervisor. This creates a layered architecture – the physical AWS infrastructure and Nitro hypervisor (L0), your EC2 instance running a hypervisor (L1), and virtual machines within that instance (L2). AWS’s Nitro System passes processor extensions, such as Intel VT-x, to instances to facilitate this process. Amazon Web Services

Benefits of Nested Virtualization

AWS highlights several use cases for nested virtualization, including:

• Running emulators for mobile applications.
• Simulating in-vehicle hardware for automobiles.
• Running Windows Subsystem for Linux on Windows workstations.

For containerized workloads, nested virtualization can be particularly useful as tools like Kubernetes and Docker often run within a virtual machine, with each container potentially running in its own VM.

Underlying Technology and Instance Types

The C8i, M8i, and R8i instances utilize Xeon 6 processors, which incorporate Intel’s Trust Domain Extensions (TDX) technology to enhance isolation between the guest operating system and the hypervisor. AWS currently supports Microsoft’s Hyper-V and the open-source KVM as L1 hypervisors.

Comparison to Other Cloud Providers

AWS is joining Azure and Google Cloud Platform in offering nested virtualization. But, Google Cloud Platform currently only supports KVM as an L1 hypervisor.

Future Considerations

While AWS currently supports Hyper-V and KVM, the possibility of adding support for VMware’s ESXi remains open. Currently, access to ESXi often requires a subscription to Broadcom’s Cloud Foundation (VCF) private cloud suite. AWS’s Amazon Elastic VMware Service provides an alternative for combining AWS and VMware technologies.