Firecracker: Getting started

This post is about how to get started using Firecracker.

Introduction

WIP.

Create/Build Kernel

Get the Linux source code at v6.19 using the recommended guest Kernel configuration (see: https://github.com/firecracker-microvm/firecracker/tree/main/resources/guest_configs).

git clone https://github.com/torvalds/linux.git
cd linux
git checkout -b v6.19 v6.19
wget 'https://raw.githubusercontent.com/firecracker-microvm/firecracker/refs/heads/main/resources/guest_configs/microvm-kernel-ci-x86_64-6.1.config' -O .config
make olddefconfig
make vmlinux

If the above fails at any point, please try either yes ““ | make oldconfig or make silentoldconfig before make vmlinux.

Create Linux rootfs image

Download pre-built Linux Kernel and rootfs

If you prefer a pre-built solution then execute the below:

# Download a linux kernel binary
wget https://s3.amazonaws.com/spec.ccfc.min/firecracker-ci/v1.7/x86_64/vmlinux-5.10.204
# Download a rootfs
wget https://s3.amazonaws.com/spec.ccfc.min/firecracker-ci/v1.7/x86_64/ubuntu-22.04.ext4
# Download the ssh key for the rootfs
wget https://s3.amazonaws.com/spec.ccfc.min/firecracker-ci/v1.7/x86_64/ubuntu-22.04.id_rsa
# Set user read permission on the ssh key
chmod 400 ./ubuntu-22.04.id_rsa

Internet within guest

Extra reading material.

1. https://github.com/firecracker-microvm/firecracker/blob/main/docs/network-setup.md#in-the-guest.

2. https://github.com/firecracker-microvm/firecracker/blob/main/docs/network-setup.md#on-the-host.

3. https://github.com/firecracker-microvm/firecracker/issues/1585.

4. https://github.com/firecracker-microvm/firecracker/blob/1afbacadfa7e9891e654928044ecfb322642c179/docs/network-setup.md?plain=1#L19.

Demo

https://github.com/firecracker-microvm/firecracker-demo/blob/main/start-firecracker.sh

References

1. https://firecracker-microvm.github.io.

2. https://github.com/firecracker-microvm/firecracker.

3. https://jvns.ca/blog/2021/01/23/firecracker--start-a-vm-in-less-than-a-second.

4. https://fly.io/blog/fly-machines.

5. https://stanislas.blog/2021/08/firecracker.