Deregister elb targets before registering targets

[DanielCKennedy]

What type of PR is this?

/kind bug

What this PR does / why we need it:

NLB's with the the max number of targets in a target group are unable to perform node replacements due to "TooManyTargets" errors short-circuiting the ensureTargetGroupTargets() function during registration, preventing the deregister action from happening.

error trying to register targets in target group: \"TooManyTargets: You cannot have more than 1000 targets per network load balancer with cross-zone load balancing enabled.

This change will perform the deregister operation before the register operation to prevent deadlock on NLB's with quota pressure.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Fixed bug that prevented target deregistrations from occurring on Load Balancer target groups with quota pressure by processing deregistrations before registrations

[k8s-ci-robot]

This issue is currently awaiting triage.

If cloud-provider-aws contributors determine this is a relevant issue, they will accept it by applying the triage/accepted label and provide further guidance.

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[k8s-ci-robot]

Hi @DanielCKennedy. 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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[kmala]

/ok-to-test

[kmala]

/lgtm

[yue9944882]

can we add a unit test that simulates the quota pressue issue and asserts that deregistration happens first? meanwhile it will be great to have some code comments clarifying the reason why we have this ordering..

[k8s-ci-robot]

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

Test name	Commit	Details	Required	Rerun command
pull-cloud-provider-aws-e2e-kubetest2	06f20a0	link	false	/test pull-cloud-provider-aws-e2e-kubetest2
pull-cloud-provider-aws-e2e-kubetest2-quick	06f20a0	link	false	/test pull-cloud-provider-aws-e2e-kubetest2-quick

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.

Details

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.

[yue9944882]

/lgtm
/approve
/retest

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: yue9944882

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