kafka-ui/documentation/compose/jaas/kafka_server.conf

KafkaServer {
    org.apache.kafka.common.security.plain.PlainLoginModule required
    username="admin"
    password="admin-secret"
    user_admin="admin-secret"
    user_enzo="cisternino";
};

KafkaClient {
    org.apache.kafka.common.security.plain.PlainLoginModule required
    user_admin="admin-secret";
};

Client {
       org.apache.zookeeper.server.auth.DigestLoginModule required
       username="zkuser"
       password="zkuserpassword";
};