title: Getting elasticsearch "can not run as root" error after upgrading from SonarQube 6.5 to 6.6. Nothing else changed
body: <p>Getting elasticsearch "can not run as root" error after upgrading from SonarQube 6.5 to 6.6. Nothing else changed.</p>
  
  <p>CentOS release 6.8 (Final)
  Java(TM) SE Runtime Environment (build 1.8.0_101-b13)</p>
  
  <pre><code>java.lang.RuntimeException: can not run elasticsearch as root
          at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:106) ~[elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:195) ~[elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:342) [elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:132) [elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:123) [elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:67) [elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:134) [elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.cli.Command.main(Command.java:90) [elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:91) [elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:84) [elasticsearch-5.6.2.jar:5.6.2]
  2017.10.20 11:59:14 WARN  es[][o.e.b.ElasticsearchUncaughtExceptionHandler] uncaught exception in thread [main]
  org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root
          at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:136) ~[elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:123) ~[elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:67) ~[elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:134) ~[elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.cli.Command.main(Command.java:90) ~[elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:91) ~[elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:84) ~[elasticsearch-5.6.2.jar:5.6.2]
  Caused by: java.lang.RuntimeException: can not run elasticsearch as root
          at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:106) ~[elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:195) ~[elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:342) ~[elasticsearch-5.6.2.jar:5.6.2]
          at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:132) ~[elasticsearch-5.6.2.jar:5.6.2]
          ... 6 more
  </code></pre>