update kubeadm pages to use registry.k8s.io

[neolit123]

k8s.gcr.io is a deprecated in favor of registry.k8s.io.
The kubeadm code in k/k was already changed to use the
new domain name.

(this is targeting 1.25)

xref kubernetes/kubeadm#2671
xref kubernetes/k8s.io#1834

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[neolit123]

/sig cluster-lifecycle
/kind deprecation cleanup

[neolit123]

/cc @pacoxu
PTAL

[pacoxu]

/lgtm

Should we mention that registry.k8s.io is currently redirecting to k8s.gcr.io somewhere? Or a link to introduce the new/old registry may help users.

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 282f80f8eb7ec2eb10b69918865c99420783a4de

[reylejano]

/milestone 1.25
/cc @kcmartin

[neolit123]

Should we mention that registry.k8s.io is currently redirecting to k8s.gcr.io somewhere? Or a link to introduce the new/old registry may help users.

We could. I think we can link to the blogpost that was discussed about it. Not sure if it's WIP already.

[SataQiu]

/lgtm

[reylejano]

@pacoxu I don't think registry.k8s.io redirects to k8s.gcr.io
See this email to dev@kubernetes.io

[neolit123]

registry.k8s.io is currently just a redirect to k8s.gcr.io.
eventually it will become the actual registry, at which point k8s.gcr.io will become the redirect to registry.k8s.io.

it's in the design doc:
https://docs.google.com/document/d/1yNQ7DaDE5LbDJf9ku82YtlKZK0tcg5Wpk9L72-x2S2k/edit#heading=h.x9snb54sjlu9

We should implement a redirect proxy server on a k8s.io subdomain. The server should initially redirect all requests to the existing k8s.gcr.io

[neolit123]

the k/k PR with action required does not have the mention of a redirect:
kubernetes/kubernetes#109938

so i think we can omit it from the k/website docs as well.

eventually i'm hoping that sig-k8s-infra will write a blog post about it.
https://github.com/orgs/kubernetes/projects/77/views/2

[reylejano]

/sig k8s-infra
Discussed in the June 2022 monthly Kubernetes community meeting
/lgtm

[RA489]

/assign @sftim for approval.

[kbhawkey]

/approve

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