Reference
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Using Finalizers Finalizers are a mechanism to execute any custom logic related to a resource before it gets deleted from Kubernetes cluster. 
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Watching Resources Watch resources in the Kubernetes cluster to be informed and take actions on changes. 
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What’s a webhook? Webhooks are HTTP callbacks, there are 3 types of webhooks in k8s: 1) admission webhook 2) CRD conversion webhook 3) authorization webhook - Admission webhook Admission webhooks are HTTP callbacks for mutating or validating resources before the API server admit them.
 
