GET should be transformed to watch in kube-Apiserver

[kkkkun]

What type of PR is this?

/kind bug

What this PR does / why we need it:

We set apiserver_longrunning_gauge's threshould to 400 which not contain watch request. When the cluster scales to 600 node, we receive a alarm which exceeds the threshould. And it show that the request is 'GET Node'. However, the 'GET Node' request should not record to apiserver_longrunning_gauge.

And then, We add log to

kubernetes/staging/src/k8s.io/apiserver/pkg/endpoints/metrics/metrics.go

Line 429 in e054181

When kubelet watch apiserver, it request contains self's 'metadata.name'. The scope would be set 'resource' and the reportedVerb finially would be set 'GET'. but requestInfo's Verb is watch. We should record this request to 'WATCH' rather than 'GET'. So here we should transform 'GET' or 'LIST' to watch when query has 'watch=true'

Which issue(s) this PR fixes:

Special notes for your reviewer:

Does this PR introduce a user-facing change?

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[kkkkun]

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done!

[kkkkun]

/release-note-none

[jfbai]

/ok-to-test

[fedebongio]

/assign @yliaog
/triage accepted

[kkkkun]

@wojtek-t @yliaog Please review. When query contains 'watch=true', LIST or GET should be transformed to WATCH. It's a better solution.

[wojtek-t]

/hold

[wojtek-t]

This isn't correct.

We don't support watch on GET verb (well - with verb in the meaning of how we treat that in kube-apiserver, because the actual http verb is GET - but it's not what we get here).

watch is only supported for LIST requests.

[kkkkun]

Here we have a kubelet's watch request just like.

/api/v1/nodes?allowWatchBookmarks=true&fieldSelector=metadata.name=test-01&resourceVersion=53658191&timeout=8m40s&timeoutSeconds=520&watch=true.

It will be recorded to GET longrunning request because It has metadata.name. But actually it is a WATCH request.
How to fix this?

[wojtek-t]

OK - I forgot that we're transforming to LIST verb only based on scope.

I'm thinking how to change that to avoid doing that for every single GET call, which we already know that is not watch.

Given that this is problematic only for:

• RecordRequestAbort
• RecordRequestTermination
• RecordLongRunning
  I think it's better to do that detection there and avoid this check here.

So in other words:

1. add a function:

// better name needed
string getVerbIfWatch(request *http.Request) {
}

that returns watch if the request is watch, "" otherwise

2. call it in those places
3. leave as is here (call that method, but only on LIST)

[kkkkun]

@wojtek-t Please review.

[wojtek-t]

Let's unify the calls across all calls and change to:

reportedVerb := cleanVerb(CanonicalVerb(strings.ToUpper(req.Method), scope), getVerbIfWatch(req), req)

[Same everywhere below]

[wojtek-t]

Let's split this part into a separate function:

func checkIfWatch(req *http.Request) bool {
if values := req.URL.Query()["watch"]; len(values) > 0 {
if value := strings.ToLower(values[0]); value != "0" && value != "false" {
return true
}
}
return false
}

And use that function both here and in line 557

[kkkkun]

done!

[wojtek-t]

One last comment - other than that LGTM

[wojtek-t]

/lgtm
/approve

[wojtek-t]

/hold cancel

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kkkkun, wojtek-t

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