AWS has written Firecracker in Rust: https://firecracker-microvm.github.io/

It's the foundation for Fargate and Lambda, so a <<ton>> of AWS customer code runs on top of it.

Considering Microsoft, Google, basically every big company backs it now, I'm sure there are other infra projects using it. They're just not all very visible because these companies only open source a small percentage of their infra.