title: Increasing Replication Factor in Kafka gives error - "There is an existing assignment running"
body: <p>I am trying to increase the replication factor of a topic in Apache Kafka.In order to do so I am using the command </p>
  
  <pre><code>kafka-reassign-partitions --zookeeper ${zookeeperid} --reassignment-json-file ${aFile} --execute
  </code></pre>
  
  <p>Initially my topic has a replication factor of 1 and has 5 partitions, I am trying to increase it's replication factor to 3.There are quite a bit of messages in my topic. When I run the above command the error is - <strong>"There is an existing assignment running"</strong>.
  My json file looks like this :</p>
  
  <pre><code>{
      "version": 1,
      "partitions": [
          {
              "topic": "IncreaseReplicationTopic",
              "partition": 0,
              "replicas": [2,4,0]
          },{
              "topic": "IncreaseReplicationTopic",
              "partition": 1,
              "replicas": [3,2,1]
          }, {
              "topic": "IncreaseReplicationTopic",
              "partition": 2,
              "replicas": [4,1,0]
          }, {
              "topic": "IncreaseReplicationTopic",
              "partition": 3,
              "replicas": [0,1,3]
          }, {
              "topic": "IncreaseReplicationTopic",
              "partition": 4,
              "replicas": [1,4,2]
          }
      ]
  }
  </code></pre>
  
  <p>I am not able to figure out where I am getting wrong. Any pointers will be greatly appreciated.</p>