[dvdbloc]

What do the big three use?

[paxys]

AWS – Nitro (based on KVM)

Google – "KVM-based hypervisor"

Azure – Hyper-V

You can of course assume that all of them heavily customize the underlying implemenation for their own needs and for their own hardware. And then they have stuff like Firecracker, GVisor etc. layered on top depending on the product line.

[daneel_w]

Some more data:

Oracle Cloud - QEMU/KVM

Scaleway - QEMU/KVM

[bonzini]

IBM cloud, DigitalOcean, Linode, OVH, Hetzner,...