Mutable state and static assets/configuration are very different things. * For state you want to mount some kind of mutable storage that outlives the container

Mutable state and static assets/configuration are very different things. * For state you want to mount some kind of mutable storage that outlives the container. * Assets/config have very similar versioning and distribution requirements as code, so sharing a mechanism makes sense. If the assets are big and change less often than the application code, using a separate image helps keep the main application image small. (Though don't know enough about docker if the specific mechanism proposed in the linked article makes sense)