It works on AWS's metal instances, doesn't it?

That is definitely a constraint though, as the smallest available metal instances are pretty large, hence costly on a per instance basis.

Technically speaking you are right. If you are not limited to AWS, then even a $5 DigitalOcean instance is be able to host 4-5 VMs.

It does work on AWS on the instances that support nested virtualization, same as every other provider.

> does not work on Amazon Web Services instances

Why not? And what is Google, Azure and DI doing differently

Firecracker relies on KVM in the Linux kernel which relies on VT-x or similar. Offering VT-x inside a VM that's already using VT-x is called nested virtualization. EC2 VMs do not support nested virtualization, while others do.

That said, it works fine on EC2 Bare Metal instances.

(n.b., I work on the virtualization stack on Google Compute Engine)

Wouldn’t you want to run firecracker on bare metal anyways. Nested VMs come with a decent perf hit.

Thanks @jsolson for explaining

@bushbaba I wonder how large the percentage hit could be, if it's like 1% or 10%, if you happen to know

And how that percentage hit compares with gvisor performance wise