title: how zookeper talk with kafka to know kafka is up
body: <p>we have with 3 kafka machine and 3 zookeper servers</p>
  
  <p>while kafka machines are not co-hosted with zookeper server ( kafka are on different machines , OS is redhat version 7.x )</p>
  
  <p>in order to get the brokers id , we do the following on the zookeper servers</p>
  
  <pre><code>cd /usr/hdp/current/zookeeper-server/bin
  
  ./zkCli.sh
  
  ls /brokers/ids
  </code></pre>
  
  <p>results should be the three brokers id's as</p>
  
  <pre><code>1011  1012  1013
  </code></pre>
  
  <p>my question is - in which way zookeper know that broker is up?</p>
  
  <p>or to be more specific</p>
  
  <p>which cli zookeper execute in order to identify that kafka broker is up ?</p>