CoreOS Container Linux is now end-of-life: what next?

CoreOS Container Linux officially reached end-of-life (EOL) on May 26, 2020. As the Red Hat EOL announcement makes clear: “Any bugs or security vulnerabilities discovered after that date will not be fixed."

If you’re running CoreOS today, it is now time to move to an alternative base operating system for your container deployments. Most options available to you today, however, have significant differences from CoreOS Container Linux. That means that in-place updates are impossible, and migration of your existing configurations require non-trivial engineering effort.

Most options, that is, except one: Flatcar Container Linux.

What is Flatcar Container Linux?

Conceived as a “friendly fork” of CoreOS, Flatcar Container Linux offers an identical user experience. Transition from existing installations is extremely simple, as every existing feature of CoreOS is taken forward - including cloud-init, Ignition, matchbox, immutable file system with A/B partition upgrades and rollbacks, and automatic update checks.

Flatcar, however, goes beyond the last version of CoreOS Container Linux, as it is actively maintained by Kinvolk’s team of Linux and container technology experts. After all, we are the team that originally collaborated with CoreOS to build the rkt container engine. We are systemd maintainers. And we have added senior engineers from AWS, Google and Red Hat to guarantee our ability to continue to develop and support Flatcar Container Linux.

As our friends at VMware put it , “Flatcar is a popular container OS and the perfect drop-in replacement to CoreOS Container Linux”.

Rapidly growing user community

Thousands of users have already adopted Flatcar as their go-forward platform. Here is what some of them have to say:

We don’t see the need to migrate to a new OS. All of the arguments about the importance of CoreOS still hold true. Flatcar is the only drop-in replacement. There is almost no work to be done to replace it. And there isn’t even an alternative. Fedora CoreOS doesn’t have a support plan yet and the list of changes one has to do is very long.

Timo Derstappen · CTO, Giant Swarm

The transition from CoreOS AMIs to Flatcar AMIs in AWS was seamless… we were fully migrated to Flatcar Linux and haven’t looked back since! Shoutouts to the whole Kinvolk team for their dedication to providing users with a seamless upgrade path.

Steve Wade · Platform Lead, Mettle

As we realized CoreOS Container Linux was reaching end of support, we reached out to the team at Kinvolk and were impressed by their commitment to the original CoreOS vision, and their ability to support us through a seamless transition to Flatcar. With a Flatcar Container Linux subscription in place, we now feel comfortable that we have a viable long-term platform strategy.

Michael Ferraro · VP Platform at UpGuard

With Flatcar Container Linux, the community now has a strong roadmap upon which to continue the momentum of CoreOS, backed by a proactive support model and the stellar Kinvolk team.

Zac Smith · CEO at Packet

CoreOS Container Linux has seen wide adoption across the industry, and many users are looking for a path forward that doesn’t entail significant operational disruption. Kinvolk has demonstrated their commitment and ability to do this with Flatcar Container Linux.

Joe Sandoval · SRE Manager, Infrastructure Platform at Adobe, and OpenStack User Committee member

Ready to come aboard?

If you’re ready to make the switch to Flatcar, please do try it out , and get in touch . We love to help users get on board, and offer a range of support options to ensure both your transition and ongoing deployment experience are trouble-free.