rpm-ostree, aka /usr/bin/atomic
A system to compose RPMs on a server side into an OSTree repository, and a client side tool to perform updates.
The project aims to bring together a hybrid of image-like upgrade features (reliable replication, atomicity), with package-like flexibility (seeing package sets inside trees, layering, partial live updates).
rpm-ostree is in beta!
While many of the underlying technologies here are stable, if you are considering using this in your organization, you should perform a careful evaluation of the whole stack. Software updates are obviously critical, and touch on many areas of concern.