Firecracker has more tooling for the orchestration layer that manages many sandboxes at once. Stuff like K8S integration, an external REST API control plane, more first-class support for snapshotting, etc.
You'd have to build more of that with libkrun
The core tech of both are great though.
Firecracker has more tooling, but setting ist up and managing it is also more complicated, at least for k8s workloads. Libkrun is so easy for k8s! Compile crun with Libkrun support, crate a symlink of crun with the name krun, done. Works like any normal pod. Firecracker with kata-containers is a lot more brittle and complicated. I've invested quite some time getting this running for a talk I'm working on
Is the talk going to be shared online anywhere? Would be interested in checking it out later!