Create garbage collection docs

content/en/docs/reference/glossary/finalizer.md

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+---
+title: Finalizer
+id: finalizer
+date: 2021-07-07
+full_link: /docs/concepts/overview/working-with-objects/finalizers/
+short_description: >
+  A namespaced key that tells Kubernetes to wait until specific conditions are met
+  before it fully deletes an object marked for deletion.
+aka: 
+tags:
+- fundamental
+- operation
+---
+Finalizers are namespaced keys that tell Kubernetes to wait until specific
+conditions are met before it fully deletes resources marked for deletion.
+Finalizers alert {{<glossary_tooltip text="controllers" term_id="controller">}}
+to clean up resources the deleted object owned.
+
+<!--more-->
+
+When you tell Kubernetes to delete an object that has finalizers specified for
+it, the Kubernetes API marks the object for deletion, putting it into a
+read-only state. The target object remains in a terminating state while the
+control plane, or other components, take the actions defined by the finalizers.
+After these actions are complete, the controller removes the relevant finalizers
+from the target object. When the `metadata.finalizers` field is empty,
+Kubernetes considers the deletion complete.
+
+You can use finalizers to control {{<glossary_tooltip text="garbage collection" term_id="garbage-collection">}}
+of resources. For example, you can define a finalizer to clean up related resources or
+infrastructure before the controller deletes the target resource.