"• Emerging VMMs (OpenBSD’s vmm, etc): Haven’t been proven in production"
It's a small operation, but https://openbsd.amsterdam/ have absolutely proven that OpenBSD's hypervisor is production-capable in terms of stability - but there are indeed other problems that rule against it on scale.
For those who are unfamiliar with OpenBSD: the primary caveat is that its hypervisor can so far only provide guests with a single CPU core.
It's a small operation, but https://openbsd.amsterdam/ have absolutely proven that OpenBSD's hypervisor is production-capable in terms of stability - but there are indeed other problems that rule against it on scale.
For those who are unfamiliar with OpenBSD: the primary caveat is that its hypervisor can so far only provide guests with a single CPU core.