kubectl run add pull-policy flag to control image pull policy

[adohe-zz]

Add support for --image-pull-policy to 'kubectl run'

Fix #30493
@pwittrock @thockin ptal

This change is

[pwittrock]

@ymqytw Please shadow this code review.

[pwittrock]

@adohe Thanks for the ping. Will review this today.

[pwittrock]

@k8s-bot node e2e test this issue: #24451

[pwittrock]

@adohe Started looking at this, will pick it up tomorrow.

[adohe-zz]

@pwittrock thanks very much.

[pwittrock]

Reviewed 3 of 3 files at r1.
Review status: all files reviewed at latest revision, 6 unresolved discussions.

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pkg/kubectl/run.go, line 620 [r1] (raw file):

  imagePullPolicy := api.PullPolicy(params["image-pull-policy"])
  if len(imagePullPolicy) == 0 {
      imagePullPolicy = api.PullAlways

We should either:

• Only set the imagePullPolicy if it is set, and leave it empty if unset (this will rely on server side defaulting)
• Set the default imagePullPolicy value in the flag default so that it is better documented what the default is

I am leaning towards the former - e.g. don't set the imagePullPolicy here if the flag is empty.

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pkg/kubectl/run.go, line 654 [r1] (raw file):

  imagePullPolicy := v1.PullPolicy(params["image-pull-policy"])
  if len(imagePullPolicy) == 0 {

Same comment here about defaulting.

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pkg/kubectl/run.go, line 911 [r1] (raw file):

  imagePullPolicy := api.PullPolicy(params["image-pull-policy"])
  if len(imagePullPolicy) == 0 {
      imagePullPolicy = api.PullIfNotPresent

Why do we use a different default here than elsewhere? Why do we set client-side defaults here but not elsewhere?

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pkg/kubectl/run_test.go, line 40 [r1] (raw file):

              "name":              "foo",
              "image":             "someimage",
              "image-pull-policy": "Always",

If we only explicitly set the value in the config when the flag is supplied, then we can get rid of most of these changes.

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pkg/kubectl/cmd/run.go, line 108 [r1] (raw file):
Explain the unset behavior. e.g.

If left empty, this value will not be specified by the client and defaulted by the server.

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pkg/kubectl/cmd/run.go, line 172 [r1] (raw file):

  if err := verifyImagePullPolicy(cmd); err != nil {
      return nil

Shouldn't this return the err?

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Comments from Reviewable

[pwittrock]

Review Pass Finished

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Review status: all files reviewed at latest revision, 6 unresolved discussions.

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Comments from Reviewable

[adohe-zz]

Thanks @pwittrock, I will update it. Besides this reviewable tool looks great.

[adohe-zz]

pkg/kubectl/run.go, line 911 [r1] (raw file):

Previously, pwittrock (Phillip Wittrock) wrote…

Why do we use a different default here than elsewhere? Why do we set client-side defaults here but not elsewhere?

I have no idea why do this for BasicPod generator, but we did do it. I just respect the old behavior.

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Comments from Reviewable

[adohe-zz]

pkg/kubectl/run.go, line 620 [r1] (raw file):

Previously, pwittrock (Phillip Wittrock) wrote…

We should either:

• Only set the imagePullPolicy if it is set, and leave it empty if unset (this will rely on server side defaulting)
• Set the default imagePullPolicy value in the flag default so that it is better documented what the default is

I am leaning towards the former - e.g. don't set the imagePullPolicy here if the flag is empty.

Agreed.

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Comments from Reviewable

[adohe-zz]

pkg/kubectl/cmd/run.go, line 172 [r1] (raw file):

Previously, pwittrock (Phillip Wittrock) wrote…

Shouldn't this return the err?

ohh~some stupid mistake I just made.

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Comments from Reviewable

[pwittrock]

Review status: all files reviewed at latest revision, 6 unresolved discussions.

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pkg/kubectl/run.go, line 911 [r1] (raw file):
Alright, sounds good for now. Consider adding a comment stating we don't know why this is specificed:

// TODO: Figure out why this is set here, and whether we can make it consistent with the other places imagePullPolicy is set using the flag

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Comments from Reviewable

[pwittrock]

Yeah I really like the new tool. It is much more powerful and allows you to do diffs against arbitrary versions.

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Review status: all files reviewed at latest revision, 6 unresolved discussions.

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Comments from Reviewable

[adohe-zz]

pkg/kubectl/run.go, line 911 [r1] (raw file):

Previously, pwittrock (Phillip Wittrock) wrote…

Alright, sounds good for now. Consider adding a comment stating we don't know why this is specificed:

// TODO: Figure out why this is set here, and whether we can make it consistent with the other places imagePullPolicy is set using the flag

Done.

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Comments from Reviewable

[adohe-zz]

pkg/kubectl/cmd/run.go, line 172 [r1] (raw file):

Previously, AdoHe (TonyAdo) wrote…

ohh~some stupid mistake I just made.

Done.

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Comments from Reviewable

[adohe-zz]

@pwittrock Just update, ptal.

[mengqiy]

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Comments from Reviewable

[pwittrock]

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Review status: 0 of 3 files reviewed at latest revision, 5 unresolved discussions.

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Comments from Reviewable

[pwittrock]

Reviewed 1 of 3 files at r2, 2 of 2 files at r3.
Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[pwittrock]

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Review status: all files reviewed at latest revision, all discussions resolved, some commit checks pending.

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Comments from Reviewable

[pwittrock]

@adohe I thin there is a way for you to mark my comments as done in Reviewable. In the future would you see if this is possible?

[adohe-zz]

@pwittrock yes, it should be possible to do that.

[k8s-bot]

GCE e2e build/test passed for commit ca315e3.

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[k8s-github-robot]

@k8s-bot test this [submit-queue is verifying that this PR is safe to merge]

[k8s-bot]

GCE e2e build/test passed for commit ca315e3.

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• Build Log
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[k8s-github-robot]

Automatic merge from submit-queue