A micro-VM generator based on buildroot

What is it?

This project allows you to generate a disk image for a minimal system based on the Linux hardened kernel, systemd and minimal busybox utilities.

It was originally created to experiment with buildroot and secure boot with systemd.

Getting started, with lots of compiling

If you do not want to be compiling for hours, you can also try the precompiled image: the easy way.

# We'll start by cloning this repo
git clone --recurse-submodules https://github.com/vdagonneau/microvmgen

# We then download the latest release of buildroot and unpack it
curl https://buildroot.org/downloads/buildroot-2021.11-rc1.tar.bz2 | tar xj

# We configure buildroot with this repo
cd buildroot-2021.11-rc1
BR2_EXTERNAL=../microvmgen make microvm_defconfig

# And we start building the toolchain and then the system
# BEWARE: this step might take a really long time to complete 
# Feel free to adjust the jobs parameter to best suit your system
make -j 24

You can now jump straight to to Running the generated image.

Getting started, the easy way

Download the latest release in the 'Releases' section on the right, unzip it in a folder and then jump to Running the generated image.

Running the generated image

In order to run the generated image you will need a UEFI firmware image as well as a pre-initialized UEFI NVRAM image.

Both these files are generally available on most Linux distros in a package called edk2-ovmf. As the NVRAM image is going to be written to by the virtual machine, it needs to be copied before being used.

cp /usr/share/OVMF/OVMF_VARS_4M.fd OVMF_VARS_4M.fd

qemu-system-x86_64 -machine type=pc-q35-6.0,accel=kvm -smp 2 \
  -nographic -serial mon:stdio \
	-drive if=pflash,format=raw,readonly=on,file=/usr/share/OVMF/OVMF_CODE_4M.secboot.fd \
	-drive if=pflash,format=raw,file=OVMF_VARS_4M.fd \
	-drive file=output/images/disk.img,if=virtio,format=raw