Open Source Summit North America 2022

This talk will take a practical look at one transition from an asymmetric to symmetric software update mechanism. Requirements include fail-safe updates, a writable data partition, support for changing files in the update images, and the preservation of configuration information across updates. These requirements led to several interesting aspects of the design. Topics will include an overview of asymmetric and symmetric software updates, the use of the open-source RAUC project to build and apply updates, and the use of the OverlayFS union mount filesystem to combine a fixed boot image and a writable data partition.