mkosi (GitHub:/systemd/mkosi) is a general purpose image builder that can be used for all kinds of workflows, including kernel hacking! The mkosi-kernel project (GitHub:/DaanDeMeyer/mkosi-kernel) intends to make hacking on the kernel as streamlined and painfree as possible. This talk will give a brief introduction to mkosi and mkosi-kernel, explaining how it can be used as a day to day tool for building and testing patches to the Linux Kernel. Unlike alternatives like virtme(-ng), instead of booting from the host rootfs, mkosi-kernel will always build a custom image and boot into that. This image can be of any distribution, with any number of packages required to test kernel changes. Additionally, this image can be booted in a virtual machine as a disk image, cpio, unified kernel image or using virtiofs. Furthermore, mkosi-kernel can build various associated userspace projects like xfstests and make these available in the booted virtual machine for easy access to integration tests. Of course mkosi-kernel will also build the kernel itself for you if requested, but a prebuilt kernel can also be provided.