Initializers are a set of tasks during the object initialization stage. They could be a set of checks or mutations to perform force policies or inject defaults. For example, you could implement an initializer to inject a sidecar container or a volume containing test data to a pod. Initializers are configured in metadata.initializers.pending for an object. After the corresponding initializer controller (identified by name) performs the task, it'll remove its name from the metadata. If for some reasonsone initializer doesn't work well, all the objects with that initializer will be stuck in ServiceAccount uninitialized stage, and not visible in the API. Use it with caution.