• Summary

    See how the leading CoreOS Container Linux alternatives stack up against each other, or scroll down to the conclusion if you just want to get to the bottom line.

    Fedora CoreOS

    Pros:

    • Comes from Red Hat
    • Active project
    • Available on wide range of platforms

    Cons:

    • Larger distro
    • No in-place update
    • No support for cloud-init
    • Many configuration changes
    • Not hardened for production by Red Hat - releases may not be fully tested compared with RHEL CoreOS
    • Relatively new project (out of preview in January 2020)
    • No commercial support available

    Flatcar Container Linux

    Pros:

    • Seamless migration from CoreOS Container Linux
    • Identical operational experience to CCL
    • Small footprint
    • Established project (>2 years)
    • Available on wide range of platforms

    Cons:

    • Backed by a smaller company than Red Hat / AWS

    RHEL CoreOS

    Pros:

    • Well integrated with OpenShift
    • Hardened for production by Red Hat
    • Available on wide range of platforms

    Cons:

    • Only supported as part of an OpenShift subscription
    • Otherwise, as for Fedora CoreOS

    AWS Bottlerocket

    Pros:

    • Supported by AWS in EC2
    • Well integrated with EKS

    Cons:

    • Only available for AWS today
    • No official support for users of non-AWS platforms
    • Very new project, not yet field hardened
  • Conclusion

    And the winner is…

     

    All of them!


    There is no single "bottom line" because the path you choose depends on your needs and use case.

     

    Instead, here are some recommendations based on some common scenarios.

  • Recommendations

    If you are using Red Hat OpenShift

    …then you should use RHEL CoreOS: it is bundled with your existing subscription, and fully integrated and supported.

    If you want a seamless in-place upgrade for an existing CoreOS Container Linux deployment

    …then Flatcar Container Linux is the only solution meeting your needs today.

    If you want to try a cutting-edge operating system with the latest features, and are willing to live with occasional regressions or breaking changes and best-efforts community support (rather than a commercial support contract)

    …then consider either Fedora CoreOS or the Flatcar Edge channel. Both are good solutions.

    If you want a container-optimized operating system with enterprise support AND you’re not using Red Hat OpenShift

    …then you should use Flatcar Container Linux with a support subscription from Kinvolk. It is the only solution offering that capability today.

    If you will only deploy on AWS, want an OS that is backed up by Amazon, and are willing to try something that’s not yet a stable, generally available release

    … then Bottlerocket may be worth a look for you. However, Fedora CoreOS or Flatcar Container Linux will both give you essentially the same functionality, but with a more mature project and from platform-neutral project teams.

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