Fedora CoreOS

Yes, Fedora CoreOS is the official community successor to CoreOS Container Linux, which was acquired and eventually retired by Red Hat. It merges the automatic update technology of CoreOS with the rpm-ostree packaging of Project Atomic. It is designed to provide a secure, immutable foundation for running containerized workloads.

While Fedora CoreOS focuses heavily on Red Hat's Podman and CRI-O for container management, Docker can be installed. However, because the OS uses an immutable rpm-ostree file system, installing Docker requires layering the package, which defeats some of the OS's security and update design. Native tools like Podman are highly recommended instead.

Updates are delivered automatically and atomically via rpm-ostree, creating a dual-partition system that allows for seamless rollbacks. When an update is downloaded and staged, the system simply reboots into the new immutable image. If an update breaks the system, the GRUB bootloader allows you to instantly select the previous working deployment.

Fedora CoreOS is configured using a specialized tool called Butane (formerly Fedora CoreOS Config transpiler). You write your configuration in a YAML format, and Butane converts it into an Ignition JSON file. The Ignition file is then passed to the server during its first boot to provision the OS, networking, and systemd services.