[from the original at: https://gandro.github.io/2015/09/27/rust-on-rumprun]
The Rust programming language has been able to run on bare-metal without the standard library for quite some while now. However, most Rust applications depend on the std crate, and therefore still need a full operating system to run.
This is where the Rumprun unikernel platform comes into play. It allows you to build your POSIX applications into bootable single-purpose images. Because unikernels are tailored to run a single application, they come without the footprint of a full-featured operating system. This makes them a great tool for application virtualization. Supported platforms of Rumprun include not only Xen/EC2 and KVM, but you can also run your image on bare-metal hardware.