791d1c81f0
Add live list of pods to PVC protection controller, as opposed to doing only a cache-based list through the Informer. Both lists are performed while processing a PVC with deletionTimestamp set to check whether Pods using the PVC exist and remove the finalizer to enable deletion of the PVC if that's not the case. Prior to this commit only the cache-based list was done but that's unreliable because a pod using the PVC might exist but not be in the cache just yet. On the other hand, the live list is 100% reliable. Note that it would be enough to do only the live list. Instead, this commit adds it after the cache-based list and performs it only if the latter finds no Pod blocking deletion of the PVC being processed. The rationale is that live lists are expensive and it's desirable to minimize them. The drawback is that if at the time of the cache-based list the cache has not been notified yet of the deletion of a Pod using the PVC the PVC is kept. Correctness is not compromised because the finalizer will be removed when the Pod deletion notification is received, but this means PVC deletion is delayed. Reducing live lists was valued more than deleting PVCs slightly faster. Also, add a unit test that fails without the change introduced by this commit and revamp old unit tests. The latter is needed because expected behavior is described in terms of API calls the controller makes, and this commit introduces new API calls (the live lists).
Kubernetes
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