Add control-plane toleration for Prometheus for Windows tests

[oprinmarius]

What type of PR is this?
/kind feature

What this PR does / why we need it:
Adds control-plane tolerations for Prometheus when running Windows Tests in Azure

Which issue(s) this PR fixes:

part of #2035

Special notes for your reviewer:

Windows Soak tests running in Azure do not spawn Linux worker nodes.
Prometheus service has to be scheduled on the control-plane nodes.

Does this PR introduce a user-facing change?:

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

Hi @oprinmarius. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[marosset]

/ok-to-test

[marosset]

/lgtm
The behavior of running windows containers on the worker nodes and linux containers on the control-plane nodes is consistent with kubernetes/kubernetes e2e tests.
This is documented at https://github.com/kubernetes-sigs/windows-testing#method-1-using-an-existing-cluster

[marosset]

/assign @mborsz @mm4tt

[jsturtevant]

can we resuse the PROMETHEUS_SCRAPE_WINDOWS_NODES? feels awkward to have to different windows scrape settings

[oprinmarius]

PROMETHEUS_SCRAPE_WINDOWS_NODE_EXPORTER is the variable we introduced when we switched to use Windows Exporter as a HostProcess and we need to use it for Azure jobs

PROMETHEUS_SCRAPE_WINDOWS_NODES variable is used by the GCE jobs to install WMI exporter on the nodes via gcloud ssh command

I used the new PROMETHEUS_SCRAPE_WINDOWS_NODE_EXPORTER variable to add taints to the control-plane nodes and to remove storage configuration for Prometheus so I don't alter the other jobs that might be running Windows tests in GCE

[jsturtevant]

thanks for the clarification. If we can eventually remove the GCE specific code and use just the hostprocess install method, we can eventually drop PROMETHEUS_SCRAPE_WINDOWS_NODES. My understanding is that GCE doesn't support hpc currently but will in the future.

[jackfrancis]

/test soak-tests-capz-windows-2019

[jackfrancis]

FYI using this PR as a guinea pig to test these changes:

https://github.com/kubernetes/test-infra/pull/26397/files#r883159740

[jsturtevant]

/lgtm

[marosset]

/lgtm

[jsturtevant]

/assign @mborsz @mm4tt

[mborsz]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jsturtevant, marosset, mborsz, oprinmarius

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• clusterloader2/OWNERS [mborsz]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment