The primary focus of Fedora CoreOS is on being a “golden image” that can be configured via Ignition to run containers. In the Fedora CoreOS model, the OS is “lifecycled” separately from the workload and configuration.
This project is explicitly designed to be derived from via container tooling, not Ignition. While we will support a “just run the golden image” flow, ading and customizing the base image with extra packages and content is the expected norm. An important corrollary to this is that OS updates are “lifecycled” with the workload and configuration.
We sometimes say that RHEL CoreOS has FCOS as an upstream but this is only kind of true; RHEL CoreOS includes a subset of FCOS content, and is lifecycled with OCP.
An explicit goal of this project is to produce bootable container images lifecycled with the base OS, that can be used as base images for RHEL CoreOS. For more on this, see e.g. https://github.com/openshift/os/issues/799
It is an explicit goal that CentOS boot also becomes a “base input” to RHEL for Edge.