fix validation for master kubelet api server

[yancl]

No description provided.

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[yancl]

I signed it!

[krisnova]

Thanks for the PR @yancl!

Will keep an eye on this and get it in ASAP

[chrislovecnm]

Need you to sign the linux foundation cla :)

[yancl]

Thanks:)

[chrislovecnm]

LGTM