Not strictly, no. While currently they only support the "hardware" in KVM/QEMU/VirtualBox, there's nothing stopping anyone implementing drivers for whatever hardware they want to run on, even bare metal.

This probably means integrating whatever Ethernet adapter you have, and some way of sending/receiving stdio, probably over serial or something.

Sideline: I'm particularly intrigued by the idea of implementing drivers for AWS EC2, so you can run this as your AMI.

> Not strictly, no. While currently they only support the "hardware" in KVM/QEMU/VirtualBox, there's nothing stopping anyone implementing drivers for whatever hardware they want to run on, even bare metal.

Exokernels (https://en.wikipedia.org/wiki/Exokernel) essentially implement this. Hardware has been adding more support for virtualization though, so I imagine unikernels are better able to take advantage of things like virtualized page tables, virtualized io-mmu, etc...

I'd be curious to see benchmarks for something generally IO bound like PostgreSQL or HyperTable. IO scheduling isn't trivial, so it might give a good idea of what some of the trade-offs might be.

> I'm particularly intrigued by the idea of implementing drivers for AWS EC2, so you can run this as your AMI.

Yup. Kind of like a skimpy version of OSv.

Yeah, how does this compare to OSv?

The kernel is way, way smaller, and has basically no OS services. OSv is more like BSD-lite.

> It still needs a 'real' OS (e.g. Linux) running as the Hypervisor.

It runs against hardware virtualization... I'm not sure I understand why it needs a "real" OS underneath. At least in theory it should be able to run on bare metal as long as you include logic for whatever device drivers you might need.

Microkernel and RTOS work shows anything it needs can be about as tiny as itself. Tinier, actually, if it's a networked service with a single app running. It already has networking, needs a driver, a few special-purpose components... not much left to add.