title: how to update config parameter of hadoop mapred-site.xml without restarting the cluster
body: <p>I would like to add/update the following parameter </p>
  
  <pre><code> &lt;property&gt;
      &lt;name&gt;mapred.map.tasks.speculative.execution&lt;/name&gt;
      &lt;value&gt;false&lt;/value&gt;
    &lt;/property&gt;
  </code></pre>
  
  <p>in mapred-site.xml in hadoop. How can I do this without restarting the cluster?</p>