Fedora 26 Atomic Host, the latest version of the Linux distribution that Red Hat uses as its proving ground for RHEL, is out. It brings with it important updates involving Kubernetes and system containers.
Fedora is an open-source project that builds a Linux distribution. Modern releases of Fedora are available in several flavors tailored for different types of deployment. Fedora’s container-centric flavor, Atomic Host, is a small-footprint operating system designed for hosting containers.
Fedora is community-supported, but Red Hat uses Fedora to help test and evaluate features that later make their way into Red Hat Enterprise Linux (RHEL) and its variants—including RHEL Atomic Host, the RHEL flavor tailored for container workloads.
Major new features in this latest version of Fedora Atomic Host include updates to the way users can run Kubernetes, as well as new system container features.
On the Kubernetes front, Atomic Host users can now run Kubernetes as a container. In previous versions of the operating system, the only way to run Kubernetes was as an application that ran directly on the host system.
Why does the change that matter? Because it makes it much easier to install and deploy Kubernetes, as well as to switch between different versions of Kubernetes. Now, if you want to change the Kubernetes version you use, you can just grab a different container image, rather than having to update system binaries (and risk dealing with RPM dependency hell).
You can still run Kubernetes the traditional way, too. You now just have more options.
Also notable is new support for system containers in Atomic Host. System containers are a way to run a virtual operating system (rather than just an individual application) inside a container.
Atomic Host’s approach to system containers is outlined here. It involves using OSTree to download and run images that contain the file systems for operating systems users want to virtualize. It’s a new take on system containers that is a bit more specific and oriented toward a particular task than are LXD, OpenVZsystem and other container platforms.
System containers on Atomic Host are interesting because they signal the interest of Fedora developers—and Red Hat too, probably—to extend container technology and concepts beyond Docker and application containers.
You can download Fedora 26 Atomic Host here.