ACK Sharding: "Invalidate" cache after moving between shards

[itaiatu]

Issue: aws-controllers-k8s/community#2545

Description of changes:

Due to the limitation (or design implementation) of k8s controller-runtime library, we have no control to hot reload / invalidate the cache of resources if a resource's labels are changed, for example.

In the sharding context of ACK controllers, by checking if that resource (from cache) still belongs to that controller, we ensure that 2 or more controllers will not overlap between each other in the context of moving a resource from one shard to another.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[ack-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[ack-prow]

Hi @itaiatu. Thanks for your PR.

I'm waiting for a aws-controllers-k8s 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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[a-hilaly]

/ok-to-test

[ack-prow]

@itaiatu: 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
verify-attribution	854f30b	link	false	/test verify-attribution

Full PR test history. Your PR dashboard.

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/test-infra repository. I understand the commands that are listed here.

[itaiatu]

/retest-required