Add --use-existing-prometheus for in-cluster PromQL

[nehadubey1338]

Measurements currently skip Prometheus unless CL2 deploys its own kube-prometheus stack. Allow querying a Service already in monitoring, with optional --prometheus-service and --prometheus-proxy-scheme. Defaults stay prometheus-k8s over http.

What type of PR is this?

/kind feature

What this PR does / why we need it:

Measurements currently skip Prometheus unless CL2 deploys its own kube-prometheus stack. Allow querying a Service already in monitoring, with optional --prometheus-service and --prometheus-proxy-scheme. Defaults stay prometheus-k8s over http.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: nehadubey1338 / name: Neha Dubey (db50286)
• ✅ login: nehadubey1338 / name: nehadubey (a81e7ce)

[kubernetes-prow]

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[kubernetes-prow]

Hi @nehadubey1338. Thanks for your PR.

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[kubernetes-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: nehadubey1338
Once this PR has been reviewed and has the lgtm label, please assign wojtek-t for approval. For more information see the Code Review Process.

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Details

Needs approval from an approver in each of these files:

• clusterloader2/OWNERS

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[alaypatel07]

@nehadubey1338 please follow the steps to get a CLA, so the EasyCLA tests passes.

[nehadubey1338]

/easycla

[alaypatel07]

/ok-to-test