I would say something like step 3 is mainly needed to get to step 4. While it doesn't have to be containers most of the implementations, as I understand them, u

I would say something like step 3 is mainly needed to get to step 4. While it doesn't have to be containers most of the implementations, as I understand them, use containers as the underlying mechanism to offer up serverless / FaaS. So you have container runtimes, microVMs (Amazon Firecracker) and... What other components are out there?