feat: Add support for h2c communications

[rsafonseca]

What this PR does / why we need it:

This PR adds support for h2c protocol. Since it's not possible to enable http2 protocol support on port 80, and h2c is a valid protocol for a number of applications, this creates the requirements for communicating with ingresses over h2c when required (e.g. clear text GRPC)

Types of changes

• New feature (non-breaking change which adds functionality)

Which issue/s this PR fixes

fixes #10429
fixes #10430
fixes #2444
fixes #9493

probably a bunch of others where folks stumble into problems due to GRPC not working with insecure connections

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• All new and existing tests passed.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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

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[k8s-ci-robot]

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[k8s-ci-robot]

Hi @rsafonseca. 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.

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[strongjz]

/ok-to-test

[rikatz]

@rsafonseca what about setting the "http2 on" directive on the server block? I am fixing it right now for nginx v1.25, and IIUC this solves the problem

[rsafonseca]

You mean as opposed to setting it on the listen line? I've been working with h2c on ingress with a custom template for a while with no issues :)

[rikatz]

Yeah, I'm generating the image with nginx v1.25 and http2 listen directive right now :) once it is ready di you mind testing it?

[k8s-ci-robot]

PR needs rebase.

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[rsafonseca]

@rikatz can you post a link to the build so I can test it Monday?

[rsafonseca]

Is this no longer the case @rikatz ? #3938 (comment)
Afaik nginx never supported http and h2c on the same port, hence this PR

[rsafonseca]

Answering myself https://hg.nginx.org/nginx/rev/08ef02ad5c54 looks like this is now possible since nginx 1.25.1 :yay: :)

[strongjz]

Is this still needed with v1.10.0 upgrading to nginx 1.25 now? If not can you close it @rsafonseca

[jetersen]

Would be very interested in how use this feature from nginx 1.25 via ingress nginx helm chart 👏