Documentation
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Overview ¶
Command fakevmm stands in for cloud-hypervisor where there is no KVM, so fiberd's cloudhv backend, the host runtime and the conformance suite run in CI as hack/hyperlight/fakehelper lets the hyperlight backend run. It serves the subset of Cloud Hypervisor's REST API the backend calls (hack/cloudhv/PROTOCOL.md) on --api-socket, takes the same flags the backend passes, and plays the guest too.
Booting runs the template from the kernel command line, after "--", as a child process, from inside the rootfs, which must be a directory here. The fake then does what the guest init does in a VM, over the unix sockets a real VMM would make: the vsock socket with its "CONNECT <port>" handshake, the control port and the endpoint port. The template reaches host port 5000, the engine, through a guest-side socket the fake forwards to <vsock socket>_5000, as a real VMM forwards a guest's connection, so the host sees the VMM as its peer. A snapshot is a config.json, a state.json and an empty memory-ranges, and a restore starts the template afresh in the phase the snapshot recorded, so park and resume round-trip. The template's memory is not carried, so a counter starts again at a resume here.
fakevmm --api-socket path=<sock> [--restore source_url=file://<dir>[,...]] [--log-file <f>] [-v] fakevmm --version
Build it static (CGO_ENABLED=0), since the backend's jail holds no libraries.
Source Files