title: Hadoop Customization overwritten by Ambari - hadoop-env.sh
body: <p>It seems a simple task: change <code>JAVA_HOME</code> in <code>/etc/hadoop/conf/hadoop-env.sh</code> to use a different version of Java.</p>
  
  <p>However, Ambari will, it seems, overwrite any changes you make in the hadoop-env.sh, by using it's templating scheme.</p>
  
  <p>The template seems to contain following line:</p>
  
  <pre class="lang-shell prettyprint-override"><code>export JAVA_HOME={{java_home}}
  </code></pre>
  
  <p>So, now if this is used to generate and replace the environment on each node, how do I define the <code>{{java_home}}</code>?</p>