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There are three main use cases for the above CLI tools, with the recommended steps, listed below:. In any case, it is assumed that the operator has stopped a node before unregistering it and does not intend to bring that node back in the near future. This is because after unregistering a node, the active controller no longer checks its supported feature levels when validating a feature upgrade. 

Remove and unregister a KRaft voter in a dynamic quorum

1. Stop the voter
2. Run kafka-metadata-quorum remove-controller with --unregister

Unregister an observer controller in a static or dynamic quorum

1. Stop the observer
2. Run kafka-cluster unregister-controller

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1. Stop the voter who was mistakenly put in controller.quorum.voters 
2. Run kafka-cluster unregister-controller
3. Ensure the stopped voter is not part of controller.quorum.voters on any other every Kafka nodes

Proposed Changes

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