title: Remove unnecessary fields in ElasticSearch
body: <p>We are populating Elasticsearch via logstash. The thing is that I see some unnecessary fields that I had like to remove like for example:</p>
  
  <pre><code>@version
  file
  geoip
  host
  message
  offset
  tags
  </code></pre>
  
  <p>Is it possible to do this by defining/extending a dynamic template? If yes, how? If no, can we do this via logstash configuration?</p>
  
  <p>Your help is much appreciated.</p>