motor-os

Motor OS is an operating system written from scratch in Rust to do exactly one thing: run inside a virtual machine. No bare metal support, no legacy drivers, no compatibility shims. A microkernel with virtio block and network drivers, and it boots in roughly a tenth of a second. Apache 2.0.

The argument behind it is that Linux inside a VM duplicates work the hypervisor already did: two layers of page tables, two schedulers making conflicting decisions, two caching layers fighting over the same memory. Motor OS drops all of that and targets x64 KVM guests on Qemu, Cloud Hypervisor, and Alioth. Today it runs Rust programs built against the standard library, tokio with TCP and UDP networking, TLS web servers, SSH, and a small set of shell utilities. The project's own website runs on Motor OS virtual machines, which is a more honest demo than a benchmark chart.

This is a research and experimentation platform, and the maintainers say so in plain language rather than burying it. Developers curious about OS internals or serious Rust systems work: clone it, because it is one of the more readable modern kernels out there. Teams: watch it, do not deploy it. Nobody should be putting customer data on this yet.

The catch is the list of things that do not exist. No security audit has been done. DHCP and DNS are unimplemented, so you assign static IPs by hand. Filesystem code is undertested by the authors' own admission, and anything reaching for Unix or Windows FFI will not build. Rust, tokio, and a static IP is the entire supported world right now. Benchmark it against Firecracker running a minimal Linux image before you conclude a microkernel was the missing piece.