title: Offsets stored in Zookeeper or Kafka?
body: <p>I'm a bit confused about where offsets are stored when using Kafka and Zookeeper. It seems like offsets in some cases are stored in Zookeeper, in other cases they are stored in Kafka. </p>
  
  <p>What determines whether the offset is stored in Kafka or in Zookeeper? And what the pros and cons? </p>
  
  <p>NB: Of course I could also store the offset on my own in some different data store but that is not part of the picture for this post.</p>
  
  <p>Some more details about my setup:</p>
  
  <ul>
  <li>I run these versions: KAFKA_VERSION="0.10.1.0", SCALA_VERSION="2.11"</li>
  <li>I connect to Kafka/Zookeeper using kafka-node from my NodeJS application.</li>
  </ul>