Debian 'mmdebstrap' Artifacts

Just a repository to make available some artifacts produced by the mmdebstrap tool, quick and easy.

The mmdebstrap does not work consistently well on OSes other than Debian. Therefore, it's easier to work with a Docker container... or simply let Github Actions does the work.

Download Artifacts: https://github.com/intjelic/debian-mmdebstrap-artifacts/actions (pick the last excecuted workflow and then pick the variation of the artifact you're interested in).

The 'mmdebstrap' tool is an alternative to 'debootstrap' to create chrootable Debian filesystems. The advantage of mmdebstrap is that it's also able to create them for different architectures other than the host architecture. Architectures such as armhf or arm64, which is useful given most of us are running on the amd64 architecture.

What are those artifacts useful for ?

Creating a Debian filesystem is one of the step needed in order to make images for VM like QEMU. Those artifacts have the particularity of providing the "boot files" (initrd and vmlinuz) that QEMU is able to use in order to boot the Debian OS without setting up more complex boot loader. The downside is that any update of the Debian system will produce updated versions of those files (when a new kernel is available in Debian package repositories).

Therefore, inside the archive, you will find a structure similar to this.

initrd.img-4.19.0-16-armmp-lpae
vmlinuz-4.19.0-16-armmp-lpae
debian-buster-standard-armhf/
  bin/
  dev/
  etc/
  home/
[...]

Where the initrd and vmlinuz files are to be passed to the QEMU's -initrd and -kernel flags. Note that you can also pass additional options to the kernel using the -append flag. Consult the QEMU documentation for more information.

Cross-architecture chrooting

Chrooting into the Debian filesystem before you make an image out of it is useful if you need to make any additional configuration such as changing the root password, creating additional system users, install more packages, set up the network interfaces, etc.

When the host has the same architecture, it's straight-forward and it can be accomplished with the following command.

sudo chroot debian-buster-standard-amd64/

When the host has a different architecture, qemu-user-static can be used easily. Assuming you're on amd64 and want to chroot into a armhf Debian filesystem, you would the following.

sudo apt-get install qemu-user-static

cp /usr/bin/qemu-arm-static debian-buster-standard-armhf/usr/bin/
sudo chroot debian-buster-standard-armhf/ qemu-arm-static /bin/bash

After you're done, you probably want to delete qemu-arm-static with sudo rm debian-buster-standard-armhf/usr/bin/qemu-arm-static.

Note that you should not rely on information provided by the uname command.

Fork and adjust to your needs

All the commands that are executed in order to create those artifacts are in the github/workflows/mmdebstrap.yml file and it can be changed as needed.

Adjust the matrix to produce only the artifacts that you need. It might get expensive if the matrix is producing too many jobs. Notably, you'll want to change the architecture and the Debian version to be installed (e.g armhf, arm64, amd64, stretch and buster).

Next, change the variant variable, to select the system packages to install. The standard value is the default for debootstrap, and values required and important are also supported. Consult mmdebstrap documentation for more information.

For a real desktop installation, you might want to use different network settings, which can also be adjusted in the matrix, use either ifupdown, systemd-networkd or network-manager. But then after, you will need to do the proper configuration too (advanced use).

While you can still chroot into the produced Debian filesystem in order to install additional packages, you can also do it right in the 'mmdebstrap' step. Add the comma-separated packages to the --include flag of the mmdebstrap tool.