Configuring mTLS authentication
Learn how to enable mTLS authentication on broker listeners with or without an external certificate.
To enable mTLS authentication on any of the broker listeners, set the
        spec.kafka.listeners[n].authentication.type property to
        tls.
#...
kind: Kafka
metadata:
  name: my-cluster
spec:
  kafka:
    listeners:
      - name: tls
        port: 9093
        type: internal
        tls: true
        authentication:
          type: tls
To use mTLS authentication using an external certificate, you need to set the type field in the
    KafkaUser resource to tls-external. A secret and credentials
   are not created for the user:
#...
kind: KafkaUser
metadata:
  name: my-user
  labels:
    strimzi.io/cluster: my-cluster
spec:
  authentication:
    type: tls-external