rancher/kuberlr-kubectl

A simple way to invoke the correct kubectl version on a Rancher managed cluster using kuberlr.

Images found at:

• https://hub.docker.com/r/rancher/kuberlr-kubectl
• https://github.com/rancher/kuberlr-kubectl/pkgs/container/kuberlr-kubectl

Details

This repo produces a Rancher specific version of the flavio/kuberlr image.

• This container is analogous to the current rancher/kubectl container, but based on kuberlr
• Unlike rancher/kubectl, this image targets specific Rancher minor release branches.
• Each release pre-bundles all necessary kubectl versions supported by the Rancher version the release supports.

Branches, Releases, and Rancher

Branch	Release Tag	Rancher Tag (Branch)
main (release/v3)	head (v3.Y.Z)	2.10.Z (main)
release/v2	v2.Y.Z	2.9.Z (release/v2.9)
release/v1	v1.Y.Z	2.8.Z (release/v2.8)

Notes:

• Each minor Rancher release will get a rancher/kuberlr-kubectl branch:
  • Each branch will get an image tag major to match it.
  • This gives us full "Y" and "Z" control on versioning the component to target Rancher minors.
  • E.x. Rancher 2.8.x releases will get varying versions of 1.Y.Z

Migration

See the dedicated Migration's Doc for specific details on migrating charts.

Compatability

The base flavio/kuberlr image comes from the upstream repo and is essentially universally compatible like kuberlr. However, for it to work it relies on an internet connection to fetch kubectl binaries on the fly.

In contrast, our rancher/kuberlr-kubectl bundles the necessary kubectl binaries into each image. In this way the image is ready to work on any supported k8s versions for that Rancher release in an air-gap out the box. Given that k8s provides a slight version drift, as the Rancher minor lifecycle progresses we reduce inclusion of older kubectl versions.

gantt
  title `rancher/rancher` and `rancher/kuberlr-kubectl`
  todayMarker off
  dateFormat X
  axisFormat 1.%S
  tickInterval 1second
  section Rancher
    2.8.X           :25,28
    2.9.X           :27,30
  section kuberlr-kubectl image
    1.Y.Z (for Rancher 2.8)   :25,28
    2.Y.Z (for Rancher 2.9)   :27,30
  section Kubectl Drift
    1.25              :24,26
    1.26              :25,27
    1.27              :26,28
    1.28              :27,29
    1.29              :28,30
    1.30              :29,31

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Note: Over-time, as new kuberlr binaries are released we can still bump the Y or Z of each rancher/kuberlr-kubectl release to update all supported Rancher releases.