title: How to know the broker that is the active controller?
body: <p>Other than using JMX is there any other way to know, whether a broker is an ActiveController?</p>
  
  <p>I know that the cluster generates a metric <code>kafka.controller:type=KafkaController,name=ActiveControllerCount</code>, but I cannot find which broker is the active controller.</p>
  
  <p>Is it necessary to write a JMX client to know it or is there another (better?) way?</p>