title: kafka-consumer-group describe results in consumer-group does not exist
body: <p>I have been trying to run the following scripts programmatically in java and for the most part they work but for some this error keeps showing up:
  "the consumer-group xyz does not exist". Could someone explain why this error is occurring especially if the consumer-group appears in the --list script.</p>
  
  <pre><code> kafka/bin/kafka-consumer-groups.sh --zookeeper 
   192.xxx.x.xxx:2181 --describe -group TEST_CONSUMER
  </code></pre>
  
  <p>Returns the error:</p>
  
  <pre><code>Error: The consumer group 'TEST_CONSUMER' does not exist.
  </code></pre>
  
  <p>But this script will list the consumer group as active:</p>
  
  <pre><code>kafka/bin/kafka-consumer-groups.sh --zookeeper 192.xxx.x.xxx:2181 --list
  </code></pre>
  
  <p>So why does it if listed, then return an error stating it does not exist? Also related to consumer-groups -- I run this script to get lag info as I was told it is not possible to get this via jmx metrics in kafka 1.0 unless I connect to each consumer server or something. Could someone verify this?</p>
  
  <p>Thanks</p>