add sts regional endpoint logic

[prasita123]

What type of PR is this?

kind bug

What this PR does / why we need it:
STS suggests using regional endpoints. (source)

AWS recommends using Regional STS endpoints to reduce latency, build in redundancy, and increase session token validity.

The PR uses sts regional endpoints, fetched using the metadata, instead of global endpoints.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Updates to the cloud-controller-manager to use regional endpoint instead of global endpoint, as AWS recommends using Regional STS endpoints to reduce latency, build in redundancy, and increase session token validity.

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[k8s-ci-robot]

Hi @prasita123. Thanks for your PR.

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[wongma7]

since this is almost identical to the passage

cloud-provider-aws/pkg/providers/v1/aws.go

Lines 1300 to 1317 in 8cdf512

	metadata, err := awsServices.Metadata()
	if err != nil {
	return nil, fmt.Errorf("error creating AWS metadata client: %q", err)
	}
	err = updateConfigZone(&cfg, metadata)
	if err != nil {
	return nil, fmt.Errorf("unable to determine AWS zone from cloud provider config or EC2 instance metadata: %v", err)
	}
	zone := cfg.Global.Zone
	if len(zone) <= 1 {
	return nil, fmt.Errorf("invalid AWS zone in config file: %s", zone)
	}
	regionName, err := azToRegion(zone)
	if err != nil {
	return nil, err
	}

could you refactor that to also use this function?

[wongma7]

/ok-to-test

[wongma7]

newline is needed her.

Run ./hack/verify-gofmt.sh locally to verify.

ref: https://prow.k8s.io/view/gs/kubernetes-jenkins/pr-logs/pull/cloud-provider-aws/313/pull-cloud-provider-aws-check/1499213287563202560

[wongma7]

consider returning multiple return values like

(string, string, err)
region, zone, err 

instead. I like it better than a special struct

[wongma7]

must check for err here

[wongma7]

I think the lack of err check causes TestNewAWSCloud to fail now after the refactor, try the test locally as well to verify .. https://prow.k8s.io/view/gs/kubernetes-jenkins/pr-logs/pull/cloud-provider-aws/313/pull-cloud-provider-aws-test/1499235237555605504

[wongma7]

/test pull-cloud-provider-aws-e2e

[wongma7]

/retest

[nckturner]

/test pull-cloud-provider-aws-e2e

[prasita123]

tested the change on a v1.22 cluster (manifest bd810fe3d5ba620f3d7cad5e4b40c11bc6efa1471d2e5075f459d29f48dca745)

• validated the sts endpoint on a newly launched instance by terminating an existing node instance of the cluster

"tlsDetails": {
        "tlsVersion": "TLSv1.2",
        "cipherSuite": "ECDHE-RSA-AES128-GCM-SHA256",
        "clientProvidedHostHeader": "sts.us-west-2.amazonaws.com"
    }

https://tiny.amazon.com/a7l9nrne/IsenLink

[wongma7]

/lgtm
but does it need a release note? maybe yes for the miniscule non-zero chance somebody has not enabled regional endpoint in opt-in region? if not put NONE in the field at the bottom of PR description

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: prasita123, wongma7

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[nckturner]

Yeah let's add one. Which reminds me... we need some mechanism to get release notes out of this don't we? I'm assuming that is buried in the kubernetes release automation but doesn't apply to other repositories.

[wongma7]

not sure it is usable outside k/k but https://github.com/kubernetes/sig-release/blob/d30b2484d7b18f869dd7f560ef5fb52a3b536a32/release-team/role-handbooks/release-notes/editing-flow.md#workflow-operation .

@prasita123 plz draft a release note, we can review that as well

[nckturner]

/test pull-cloud-provider-aws-check

[nckturner]

/test pull-cloud-provider-aws-check