mkosi — Build Bespoke OS Images

A fancy wrapper around dnf --installroot, debootstrap, pacstrap and zypper that generates customized disk images with a number of bells and whistles.

For a longer description and available features and options, see the man page.

Installation

Installing mkosi is easy, as it has no runtime Python dependencies (you will need all the tools to format filesystems and bootstrap the distribution appropriate for your image, though).

If you just want the main branch you can run

python3 -m pip install --user git+https://github.com/systemd/mkosi.git

If you want to hack on mkosi do

# clone either this repository or your fork of it
git clone https://github.com/systemd/mkosi/
cd mkosi
python3 -m pip install --user --no-use-pep517 --editable .

This will install mkosi in editable mode to ~/.local/bin/mkosi, allowing you to use your own changes right away.

For development you also need mypy, for type checking, pytest, to run tests, and black, for code formatting. We check tests, typing and code formatting in CI (see .github/workflows), but you can run the tests locally as well.

zipapp

You can also package mkosi as a zipapp that you can deploy anywhere in your PATH. Running this will leave a mkosi binary in builddir/

tools/generate-zipapp.sh

Python module

Besides the mkosi binary, you can also call mkosi via

python -m mkosi

when not installed as a zipapp.

Please note, that the python module exists solely for the usage of the mkosi binary and is not to be considered a public API.

git blame

When using git blame, be sure to add --ignore-revs-file .git-blame-ignore-revs to the arguments to ignore irrelevant code formatting commits. This can be set permanently via the blame.ignoreRevsFile git option.

References

• Primary mkosi git repository on GitHub
• mkosi — A Tool for Generating OS Images indroductory blog post by Lennart Poettering
• The mkosi OS generation tool story on LWN