Amazon Web Services (AWS) has expanded the capabilities of its EC2 compute instances by enabling nested virtualization for a select range of configurations. This feature, which allows running a hypervisor within another hypervisor, provides a powerful environment for testing, simulation, and specialized workloads like mobile application emulation and automotive hardware simulation. The move brings AWS in line with competitors like Microsoft Azure and Google Cloud Platform, though Google currently only supports KVM as a nested hypervisor.
Nested virtualization isn’t a latest concept, but its availability on AWS’s C8i, M8i, and R8i instances marks a significant step for enterprise users. It allows for the creation of complex, interconnected virtual machine environments mirroring many enterprise IT setups. AWS suggests the technology is also beneficial for containerized workloads, where tools like Kubernetes and Docker often run within virtual machines, with each container potentially residing in its own VM.
The rollout leverages Intel’s Xeon 6 processors, equipped with Trust Domain Extensions (TDX) technology, to enhance isolation between the guest operating system and the hypervisor. AWS’s own Nitro hypervisor, which underpins all EC2 instances and manages hardware allocation, plays a crucial role in enabling this functionality. According to an AWS user guide, the nested virtualization architecture operates across three layers: the physical AWS infrastructure and Nitro hypervisor (L0), the EC2 instance running a hypervisor (L1), and the virtual machines created within that instance (L2).
Currently, AWS supports Microsoft’s Hyper-V and the open-source KVM as L1 hypervisors. This opens the possibility for supporting VMware’s ESXi, a popular hypervisor in enterprise environments, though its licensing model under Broadcom has been restrictive. Analysts suggest that the Amazon Elastic VMware Service may remain the primary pathway for integrating VMware technologies with AWS for the foreseeable future.
What is Nested Virtualization and Why Does it Matter?
Nested virtualization allows users to run virtual machines inside of other virtual machines. This is particularly useful for creating isolated test environments, simulating complex systems, and running specialized applications that require a specific virtualized infrastructure. For example, developers can use it to test software across multiple operating systems without needing dedicated hardware for each. The ability to run Windows Subsystem for Linux (WSL) on Windows workstations is another cited use case.
AWS Infrastructure and the Nitro System
All EC2 instances are powered by AWS’s Nitro System, a custom-built hypervisor designed to efficiently allocate and manage hardware resources. The Nitro System is largely invisible to users, operating behind the scenes to deliver scalable and reliable compute capacity. To support nested virtualization, the Nitro System now passes processor extensions, such as Intel VT-x, to instances, enabling the creation of nested virtual machines. This builds upon AWS’s existing support for virtual machines on its bare metal instances.
Compatibility and Future Outlook
While AWS currently supports Hyper-V and KVM as L1 hypervisors, the potential for adding support for VMware’s ESXi remains a topic of interest. Broadcom’s licensing approach for ESXi, often requiring it as part of the Cloud Foundation (VCF) suite, presents a challenge. However, the demand for ESXi within enterprise environments could incentivize AWS to find a solution. The addition of nested virtualization to AWS EC2 instances provides greater flexibility and control for developers and IT professionals managing complex virtualized workloads.
The expansion of nested virtualization options across major cloud providers signals a growing demand for flexible and isolated compute environments. As organizations continue to adopt cloud-native technologies and containerization strategies, the ability to efficiently manage and orchestrate virtual machines will turn into increasingly critical.
What challenges will AWS face in integrating VMware’s ESXi, and how will this impact enterprise adoption of nested virtualization on its platform? Share your thoughts in the comments below.
