Fedora CoreOS is the combination of the underlying technology of CoreOS Container Linux and Fedora Atomic Host; which after Red Hat's acquisition of CoreOS, was initially released as a preview version.
Red Hat subsequently made Fedora CoreOS available for general use, while announcing the scheduled end-of-life support for CoreOS and Fedora Atomic Host, with Fedora CoreOS as the official replacement and successor to both of them.
As scheduled, CoreOS received its last updates on May 26 and will no longer get patches for any bugs or vulnerabilities going forward, and after September 1, Red Hat will take down all CoreOS image listings from marketplaces such as Amazon AWS, Azure, and Google Compute Engine.
Therefore, it is recommended that all Fedora Atomic Host and CoreOS users should switch to Fedora CoreOS, which will be automatically-updated, and serves as a multi-platform operating system for running containerized workloads at scale.
How to Migrate from CoreOS to Fedora CoreOS
Fedora CoreOS is the official successor of CoreOS Container Linux, which reached its end of life on May 26, 2020. It is recommended that users should follow the steps below to migrate from CoreOS to Fedora CoreOS.
If you are switching from CoreOS Container Linux, you must first convert your old Ignition configs, Container Linux Configs, or cloud-config files to a Fedora CoreOS Config (FCC) and adapt the contents for FCOS. And as many of the configuration details have changed, you must also reference this through the CL migration issue on GitHub.
The following installation changes will be made as follows: the coreos-install script will be replaced with coreos-installer, which offers similar functionality. The coreos.autologin kernel command-line parameter is not currently supported in FCOS, so to access recovery purposes, follow the instructions available here.
And certain CL platforms, like Vagrant, are not currently supported in FCOS. You should refer to the download instructions to see the available image types.
However, if you’re trying Fedora CoreOS for the first time, you'll need to download the ISO image for a fresh installation. It is multi-platform compliant, which means, you can deploy it on a variety of platforms such as VMware, Cloud image, OpenStack, and bare-metal hardware.