feat: make LeaseDuration configurable via --leader-election-lease-duration flag

[gjbravi]

Issue

resolves #3823

Description

This PR adds a new flag to the controller, --leader-election-lease-duration will be responsible for externalizing and controlling the LeaseDuration of a Lease owned by aws-load-balancer-controller.

--leader-election-lease-duration defaults to 15s if not informed, matching the default value of a LeaseDuration from controller-runtime.

Checklist

• Added tests that cover your change (if possible)
• Added/modified documentation as required (such as the README.md, or the docs directory)
• Manually tested
• 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?! 🤯

• Backfilled missing tests for code in same general area 🎉
• Refactored something and made the world a better place 🌟

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: gjbravi / name: Guilherme Bravi (998c61b, f8c0943, e233345, cc37027, 283e467)

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[gjbravi]

The AWS LB controller chart version from eks-charts repo points to 1.8.2 as follows:

https://github.com/aws/eks-charts/blob/master/stable/aws-load-balancer-controller/Chart.yaml#L4

While, here is still on 1.7.1:

aws-load-balancer-controller/helm/aws-load-balancer-controller/Chart.yaml

Lines 1 to 5 in e1d32f4

	apiVersion: v2
	name: aws-load-balancer-controller
	description: AWS Load Balancer Controller Helm chart for Kubernetes
	version: 1.7.1
	appVersion: v2.7.0

I would really appreciate some guidance on how the chart bump should be made. Ty

[shraddhabang]

/ok-to-test

[shraddhabang]

/lgtm
/approve

[gjbravi]

@shraddhabang thanks for reviewing!

I've also submitted the chart bump on f8c0943 alongside all changes made and the PR labels were removed. Could you please re-check it? Ty

[oliviassss]

@gjbravi, thanks for the contribution, I left some minor comments, overal LGTM

[shraddhabang]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: gjbravi, shraddhabang
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[caiofralmeida]

/lgtm /approve

@shraddhabang the approved label is missing (maybe should be "/approved" ?), could you help us to make this PR mergeable?

[oliviassss]

@gjbravi, hi sorry for the late response. I have a concern over the specified default duration as 15s, I think it may cause backward compatibility, especially for users who might already specify the duration in their setup. A better option is that we make this flag an opt-in, with no default value, and if it's not specify, the controller should just behave as-is now, this could mitigate the risk to change existing user behavior. Thanks.

[gjbravi]

@oliviassss tks for reviewing.

The current behavior should be equal to the default value brought by controller-runtime as far as I see. Implying that, if not specified in the values file, it will take the default value of 15 seconds.

During the implementation, I've also tested setting a "null" value to the const, however the time pkg does not allow that, forcing me to specify a value(same as the implementation of SyncPeriod).

I can perhaps be missing something here, please let me know in case another solution is also viable here. Tks