Controller: Use Protocol Buffers for API access.

[tosi3k]

What this PR does / why we need it:

If not specified explicitly, JSON encoding is used by default when talking to kube-apiserver.

For core K8s API objects like Pods, Nodes, etc., we can use protobuf encoding which reduces CPU consumption related to (de)serialization, reduces overall latency of the API call, reduces memory footprint, reduces the amount of work performed by the GC and results in quicker propagation of objects to event handlers of shared informers.

For CRDs, however, we still have to stick to JSON since they do not support protobuf encoding.

Standard system components of K8s default their serialization method to protobuf for some time already:

• kube-scheduler: link
• kubelet: link
• kube-proxy: link
• kube-controller-manager: link and method's contents

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• CVE Report (Scanner found CVE and adding report)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation only

Which issue/s this PR fixes

No issue is opened for that.

How Has This Been Tested?

Unit tests.

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have added unit and/or e2e tests to cover my changes.
• All new and existing tests passed.

[k8s-ci-robot]

This issue is currently awaiting triage.

If Ingress contributors determines this is a relevant issue, they will accept it by applying the triage/accepted label and provide further guidance.

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[netlify]

✅ Deploy Preview for kubernetes-ingress-nginx canceled.

Name	Link
🔨 Latest commit	07a56c9
🔍 Latest deploy log	https://app.netlify.com/sites/kubernetes-ingress-nginx/deploys/67643482f6c0c7000825ee65

[strongjz]

/ok-to-test
/kind feature

@rikatz or @tao12345666333 can you review this one?

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: tosi3k
Once this PR has been reviewed and has the lgtm label, please assign strongjz for approval. For more information see the Kubernetes Code Review Process.

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[tosi3k]

/test pre-ingress-nginx-codegen

[tosi3k]

/test pre-ingress-nginx-codegen

[Gacko]

Please do not commit these as long as you didn't change the go.mod.

[tosi3k]

Done - I was trying to fight with the failing pre-ingress-nginx-codegen presubmit through that but to no avail.

[tosi3k]

@Gacko would you know why this presubmit fails?

We don't require any new modules in go.mod with this change and the presubmit fails even more mysteriously.

[k8s-ci-robot]

@tosi3k: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pre-ingress-nginx-codegen	07a56c9	link	true	/test pre-ingress-nginx-codegen

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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-sigs/prow repository. I understand the commands that are listed here.