What is Nested Virtualization?

Nested virtualization allows you to run a hypervisor within a Crusoe Cloud VM. This means you can launch your own virtual machines (L2 VMs) inside a Crusoe-provided VM (L1 VM), creating a flexible, testable, and powerful virtualization layer.

1. What use cases benefit from nested virtualization?

• Running custom hypervisor workloads

• Isolated software testing environments

• Simulating infrastructure within VMs

• Hardware passthrough and virtualization tuning

2. Which hypervisors are supported?

Supported:

• Cloud Hypervisor (as the L2 hypervisor)

Not supported:

• QEMU

• Hyper-V

• SR-IOV / MIG in L2 VMs

3. How do I enable nested virtualization in Crusoe Cloud?

Use the Crusoe CLI (v0.27.0+) and add the following flag during VM creation:

crusoe compute vms create \
  --type l40s-48gb.10x \
  --image ubuntu22.04:latest \
  ...
  --virtualization-features nested_virtualization=true

Note: A feature flag is required — contact support@crusoecloud.com to request access.

4. Does Crusoe provide internet to L2 VMs?

No. Users are responsible for configuring internet connectivity in their nested VMs. This may involve bridging, NAT, or setting up a proxy within the L1 VM.

5. Which OS images are compatible?

Nested virtualization and virtio-iommu are only supported on Ubuntu 22.04+.
Ubuntu 20.04 is not supported.

6. Are there instance types we do not recommend using?

Yes — we do not recommend using nested virtualization on H100-sxm or A100-sxm instance types. These GPUs are optimized for high-performance workloads, and nested virtualization may introduce unnecessary complexity, reduce performance, and impact system-level stability when combined with VFIO passthrough and virtio-iommu constraints.