Are you trying to have CFK (Confluent operator for Kubernetes) take over management of an existing Confluent cluster ? If yes, that is not supported.
Are you trying to have CFK to manage an Apache Kafka (not Confluent) cluster ? That is not supported either. Strimzi would be the way to go for that ?
Is there a particular feature of CFK you were interested in ?
If you want to use CFK to manage Connect backed by existing kafka cluster or to manage topics on existing kafka cluster. That may be doable https://www.confluent.io/blog/resource-management-with-confluent-for-kubernetes/
