Running OSv on Firecracker

The easiest way to run OSv on Firecracker is to use a Python script firecracker.py. The firecracker.py automates process of launching firecracker VMM executable and submitting necessary REST api calls over UNIX domain socket to create and start OSv micro-VM. For insight of why this script does what it does look at Firecracker quick start guide.

Step 0: Prerequisites

In order to run OSv on Firecracker you need bare-metal machine (AWS i3.metal or alike EC2 instance) with Linux installed and KVM enabled and OSv build environment to build arbitrary images. Alternatively one can use Mikelangelo capstan to build images. In short if one has already OSv development environment ready, firecracker should work out of the box. The firecracker.py will automatically install version 0.15.0 of Firecracker unless you point to an alternative location of firecracker executable through FIRECRACKER_PATH variable.

Step 1: Building and running

There is nothing special about building OSv images to run them on Firecracker. However please bear in mind is that Firecracker boots OSv by directly executing build/release/loader.elf (which conforms to Linux vmlinux 64-bit ELF format) instead of usr.img used by QEMU and other hypervisors. The build/release/usr.raw file (the raw version of usr.img) is used to mount a disk from is one build OSv zfs or rofs image.