fix: extract kubelet and kubectl binaries from hyperkube's binary folder when possible

[chewong]

Reason for Change:

With kubernetes/kubernetes#84662, we can no longer obtain kubelet and kubectl binaries by renaming the hyperkube binary. Instead, we should extract them through hyperkube's binary folder when possible.

Issue Fixed:

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Notes:

[mboersma]

See also #2191, which is necessary for 1.17.0-alpha.2 and later, but is currently blocked until #2161 merges.

[chewong]

@mboersma thanks for the info. Are we still planning to support customHyperkubeImage after when provided?

[mboersma]

Are we still planning to support customHyperkubeImage...?

It's a good question, since there is no official hyperkube image for 1.17 onward. I guess the most backward-compatible decision would be to continue to honor customHyperkubeImage regardless, so if the user actually builds a custom 1.17.x hyperkube image that will still work.

[codecov]

Codecov Report

Merging #2298 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2298   +/-   ##
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  Coverage   71.61%   71.61%           
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  Files         142      142           
  Lines       24760    24760           
=======================================
  Hits        17731    17731           
  Misses       5901     5901           
  Partials     1128     1128

[jackfrancis]

Just to insert myself where I wasn't invited... we should continue to support hyperkube images (including "bring your own hyperkube") indefinitely.

[mboersma]

@chewong since there isn't a hyperkube for 1.17 (except 1.17.0-alpha.1), is this a useful change?

[chewong]

@chewong since there isn't a hyperkube for 1.17 (except 1.17.0-alpha.1), is this a useful change?

We could still build a hyperkube image in 1.17 using this Dockerfile after building component binaries in k8s/k8s. This PR accounts for the new hyperkube introduced by kubernetes/kubernetes#84662. However, the long term solution is to move away from building hyperkube in k8s/test-infra and build individual components instead.

[mboersma]

Thanks for the explanation. If this helps with upstream testing even temporarily, that's important.

[mboersma]

/lgtm

[acs-bot]

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