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Comment by rbbydotdev | Hacker News Reader

> The catch is that regular EC2 is already a VM. AWS runs our host inside its own isolation layer, and then we run browser VMs inside that host. In other words, every browser is a VM inside a VM.

yes but i think there is specifically some ec2s which give you hypervisor access and thereby firecracker too - someone correct me if im wrong?

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yes only c8i, m8i and r8i instance types support it. It is called nested virtualization[1]

[1] https://aws.amazon.com/about-aws/whats-new/2026/02/amazon-ec...

Unfortunately supply is quite limited. If you want to horizontally scale on these instances you need to have a good relationship with AWS so they'll give you a big allocation before c9i is a thing.

I haven't personally tried, so I can't say for certain, but Lambda has publicly stated they run on bare metal EC2 instances, presumably the supply of whatever instance types they use should be fairly healthy

You're talking about AWS Lambda?

- Their use of bare metal isn't necessarily the latest gen hardware - AWS Lambda is part of AWS, and obviously has privileged access to supply

The interesting part to me is less the exact hardware generation and more the control plane around placement, isolation, and startup latency. That is hard to copy outside AWS.

also i found them much less stable than metal instances running into weird kvm failures

Yes, it is. It was a challenge to make it work smooth without metal. The scaling out speed was one of the main reasons

When we had need of quite big machines (AWS metal instances), we've found the performance differential between metal, and the equivalent size VM was 10-20% for CPU heavy workloads.

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