I don't understand how this works in the case of testing many applications running on many machines, where many services on many machines need to communicate with each other. We deploy a mix of systemd services and OCI containers (running on podman and Docker) to different machines, the exact mix on each machine depends on the machine's intended purpose.

We currently run CI tests using QEMU VMs. These VMs comprise a few systems representative of those that we deploy to production.

Does adopting Antithesis mean that all non-containerized applications would need to be OCI-ified and every interaction would need to be mocked? There's a sort of combinatorial explosion that I'm concerned about when I'm thinking about testing/adding a new service to a system: All services on which it depends need to be mocked and all services which depend on it require creating a mocked version of it.

Seems like a lot of work. Can someone please help clarify things for me?

Also, how could we test the behavior of non-application code like drivers or the kernel itself?