Enable having multiple matching certs in autodiscover mode

[LechG]

Issue

https://github.com/kubernetes-sigs/aws-load-balancer-controller/issues/1598

Description

When you don't provide the annotation for certificate arn, the controller tries to find a matching certificate in ACM by itself. However when multiple matching certs are found - it fails with "multiple certificate found for host: host, certARNs: [arn1, arn2]"

Which I believe is wronge because:

1. YOU CAN add multiple certificates via annotation
2. AWS has it's own algorithm of determining the best certificate to be used for the requests

To adjust this behavior, I removed the if clause that threw an error during setup of ALB in case there was more than one domain matching certificate in ACM.

Checklist

• [ ] Added tests that cover your change (if possible)
• [X] Added/modified documentation as required (such as the README.md, or the docs directory)
• [X] Manually tested
• [X] Made sure the title of the PR is a good description that can go into the release notes

BONUS POINTS checklist: complete for good vibes and maybe prizes?! :exploding_head:

• [ ] Backfilled missing tests for code in same general area :tada:
• [ ] Refactored something and made the world a better place :star2:

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• :white_check_mark: LechG (d65c203921ee89922d73bc429c860864262eaf07, a7e4f3ef7f29fee36cfcd1d82a10dd8a3cc80429)

[k8s-ci-robot]

Hi @LechG. Thanks for your PR.

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[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: LechG To complete the pull request process, please assign kishorj after the PR has been reviewed. You can assign the PR to them by writing /assign @kishorj in a comment when ready.

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[linux-foundation-easycla[bot]]

• :white_check_mark: LechG (d65c203921ee89922d73bc429c860864262eaf07, a7e4f3ef7f29fee36cfcd1d82a10dd8a3cc80429)

• :x: The commit (73a1458ab88c653fcc1e88a70c0ba88e16c4ead5) is missing the User's ID, preventing the EasyCLA check. Consult GitHub Help to resolve.For further assistance with EasyCLA, please submit a support request ticket.

[allupaku]

Hello team, any specific version , this will get merged into ? We are also looking forward for this

[k8s-ci-robot]

@LechG: PR needs rebase.

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/lifecycle stale

[k1rk]

/remove-lifecycle stale

[k8s-triage-robot]

The Kubernetes project currently lacks enough contributors to adequately respond to all issues and PRs.

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/lifecycle stale

[blakepettersson]

/remove-lifecycle stale

[blakepettersson]

@kishorj @M00nF1sh apart from the conflict with master and the CLA, what would be the showstopper to get this in?

[k8s-triage-robot]

The Kubernetes project currently lacks enough contributors to adequately respond to all issues and PRs.

This bot triages issues and PRs according to the following rules:

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/lifecycle stale

[blakepettersson]

/remove-lifecycle stale

[kishorj]

@LechG, thanks for your contribution. We will relax the single cert per host restriction in the v2.5.0 release, PR #3028 will address this. Closing this PR in favor of 3028.