reUpNix: Reconfigurable and Updateable Embedded Systems

Niklas Gollenstede, Ulf Kulau, Christian Dietrich

Abstract: Managing the life cycle of an embedded Linux stack is difficult, as we have to integrate in-house and third-party services, prepare firmware images, and update the devices in the field. Further, if device deployment is expensive (e.g. in space), our stack should support multi-mission setups to make the best use of our investment. With reUpNix, we propose a methodology based on NixOS that provides reproducible, updateable, and reconfigurable embedded Linux stacks. For this, we identify the shortcomings of NixOS for use on embedded devices, reduce its basic installation size by up to 86 percent, and make system updates failure atomic and significantly smaller. We also allow integration of third-party OCI images, which, due to fine-grained file deduplication, require up to 24 percent less on-disk space.