title: error while starting kafka broker
body: <p>I was able to successfully set up zookeeper and one kafka broker yesterday. Everything worked as expected. I shut down kafka (ctrl + c) and then zookeeper.</p>
  
  <p>Today I started zookeeper and when I started kafka (<code>bin/kafka-server-start.sh config/server0.properties</code>), I get the following error. I tried various remedies suggested (removing completely my kafka installation and doing it again from scratch). Still I get same error.</p>
  
  <pre><code>[2016-09-28 16:15:55,895] FATAL Fatal error during KafkaServerStartable startup. Prepare to shutdown (kafka.server.KafkaServerStartable)
  java.lang.RuntimeException: A broker is already registered on the path /brokers/ids/0. This probably indicates that you either have configured a brokerid that is already in use, or else you have shutdown this broker and restarted it faster than the zookeeper timeout so it appears to be re-registering.
          at kafka.utils.ZkUtils.registerBrokerInZk(ZkUtils.scala:305)
          at kafka.utils.ZkUtils.registerBrokerInZk(ZkUtils.scala:291)
          at kafka.server.KafkaHealthcheck.register(KafkaHealthcheck.scala:70)
          at kafka.server.KafkaHealthcheck.startup(KafkaHealthcheck.scala:51)
          at kafka.server.KafkaServer.startup(KafkaServer.scala:244)
          at kafka.server.KafkaServerStartable.startup(KafkaServerStartable.scala:37)
          at kafka.Kafka$.main(Kafka.scala:67)
          at kafka.Kafka.main(Kafka.scala)
  [2016-09-28 16:15:55,896] INFO [Kafka Server 0], shutting down (kafka.server.KafkaServer)
  </code></pre>
  
  <p>All set up in mac</p>