title: How to get Nutch 2.3.1 to work with ElasticSearch 5.3.2?
body: <p>I have got ElasticSearch 5.3.2 up and running on Ubuntu 16.04 and would like to use Nutch to crawl websites. I have compiled Nutch 2.3.1 and got it to successfully crawl a site, however when I go to index it into Elastic, I get errors.</p>
  <p>Command:</p>
  <p>bin/nutch index -all</p>
  <p>Output:</p>
  <p><a href="https://i.stack.imgur.com/E4phK.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/E4phK.png" alt="nutch-error" /></a></p>
  <p>In the /var/logs/elasticsearch/elasticsearch.log file I get this message:</p>
  <p><a href="https://i.stack.imgur.com/QJA9Y.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QJA9Y.png" alt="elasticsearch log file" /></a></p>
  <p>Does anyone know what this error means and how to fix this issue? Thx</p>