Support cluster using network resources (VNet, LB, IP, etc.) across AAD Tenants.

[bowen5]

What type of PR is this?
/kind feature

What this PR does / why we need it:
This PR is on target to enable the scenario that Kubernetes Clusters deployed on Azure can create/use Azure Network Resources (VNet, LB, IP, RouteTable, etc.) in a different AAD Tenant than the one cluster located in.

Which issue(s) this PR fixes:

N/A

Special notes for your reviewer:
This PR need to catch Kubernetes release v1.18. Thank you.

Does this PR introduce a user-facing change?:

Azure Cloud Provider now supports using Azure network resources (Virtual Network, Load Balancer, Public IP, Route Table, Network Security Group, etc.) in different AAD Tenant and Subscription than those for the Kubernetes cluster. To use the feature, please reference https://github.com/kubernetes-sigs/cloud-provider-azure/blob/master/docs/cloud-provider-config.md#host-network-resources-in-different-aad-tenant-and-subscription.

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

Usage: https://github.com/kubernetes-sigs/cloud-provider-azure/blob/master/docs/cloud-provider-config.md#host-network-resources-in-different-aad-tenant-and-subscription

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @bowen5. Thanks for your PR.

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[andyzhangx]

/priority important-soon
/sig cloud-provider
/area provider/azure
/ok-to-test

[andyzhangx]

@bowen5 looks like bazel is broken, pls run following check first before sending out PR:

hack/verify-golint.sh
hack/verify-gofmt.sh
hack/update-bazel.sh

[bowen5]

could you also add a release note at the PR body?

Done. Thank you.

[andyzhangx]

/test pull-kubernetes-e2e-aks-engine-azure

[bowen5]

/retest

[bowen5]

/retest

[bowen5]

/test pull-kubernetes-verify

[feiskyer]

looks good, thanks for addressing comments. Could you squash the commits?

[feiskyer]

/milestone v1.18

[bowen5]

looks good, thanks for addressing comments. Could you squash the commits?

Sure. Done. Thank you.

[feiskyer]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: bowen5, feiskyer

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Needs approval from an approver in each of these files:

• staging/src/k8s.io/legacy-cloud-providers/azure/OWNERS [feiskyer]

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[saschagrunert]

Hey @bowen5 👋, may I ask you to remove the Yes. from the release notes block? It will occur 1:1 on the release notes and we probably do not want to start the note with "Yes." :)

The explicit Action Required: None. is also not needed if no action is required :)

See:
https://github.com/kubernetes/kubernetes/blob/release-1.18/CHANGELOG/CHANGELOG-1.18.md#changelog-since-v1180-beta0

[bowen5]

Hey @bowen5 👋, may I ask you to remove the Yes. from the release notes block? It will occur 1:1 on the release notes and we probably do not want to start the note with "Yes." :)

The explicit Action Required: None. is also not needed if no action is required :)

See:
https://github.com/kubernetes/kubernetes/blob/release-1.18/CHANGELOG/CHANGELOG-1.18.md#changelog-since-v1180-beta0

Hey @saschagrunert , sorry about that as I'm new to this project :). I've rephrased the release notes section to make it more user friendly. Meanwhile, would you please kindly guide me that how could I make change if I want the statement in my release notes only appear in "Changes by Kind" -> "Feature" section instead of "Urgent Upgrade Notes" section? Since I think this change is only important for those who want to use this feature but not for all K8s audience. Putting in "Urgent Upgrade Notes" section might introduce unnecessary noise to them. Thank you!

[saschagrunert]

Thank you 🙏 @bowen5 I think we’re all set. Now the note will only appear in the kind/feature section if we re-generate them. If you want, then you could adjust the note manually in two PRs for the master and release-1.18 branch. :)

[bowen5]

Awesome, I'll leave the re-generation flow to do that. Thank you @saschagrunert !