Earlier quoted context omitted.
> How are people using this flexibility to get things done in practice Um... to loop back to the upthread point: Docker. People are using Docker, and docker is using this stuff.
And how is it mixing and matching these APIs? Given that there's an OCI-compatible runner for jails (runj, compatible with runc -- which is what docker uses to start containers), it seems to me that Docker isn't in actually using the flexibility afforded by the APIs here, but is just using a relatively fixed set of options. If I'm wrong: what is it using, and what problems is this flexibility solving?
And runj, IIRC (though I'm not an expert in the space) wasn't a trivial 1:1 thing and required changes to the underlying jails layer to enable it.