Kafka: What do the numbers in controller_epoch and leader_epoch mean?
<p>Kafka updates the state information in zookeeper as below. What do the _epoch numbers really mean? The Kafka documentation does not seems to have a good explanation of the terms.</p>

<pre><code>[zk: localhost:2181(CONNECTED) 69] get /brokers/topics/my-topic/partitions/1/state
{"controller_epoch":29,"leader":2,"version":1,"leader_epoch":28,"isr":[2,1,0]}
</code></pre>