A quick overview of how RAUC uses libcomposefs to handle new use-cases.Traditionally, RAUC focused on A/B updates for whole partitions, either byusing filesystem images or tar archives. While the image-based OS approachhas many benefits, there are scenarios where more loosely coupled componentsneed to be handle in addition to the root filesystem.In RAUC, these can be handled with using the new "artifact updates" support.As a system might have many artifacts installed in parallel, such as forcontainers (systemd-nspawn or otherwise) and systemd-sysexts, efficient storageis important. In many cases, these are updated often, so download efficiency isimportant as well.After evaluating multiple alternatives, we've now decided to integrate composefs.Besides solving the requirements above, it additionally provides the same levelof integrity protection as a dm-verity root filesystem, which is important insystems using secure boot.This talk will show how RAUC uses libcomposefs and the new use-cases supportedby having an efficient content-addressed backing store with full authentication.Licensed to the public under https://creativecommons.org/licenses/by/4.0/de/about this event: https://cfp.all-systems-go.io/all-systems-go-2024/talk/3DKX9V/