title: How AWS EMR resize
body: <p>I have some question in mind while using AWS EMR today.</p>
  
  <p>EMR provide very simple way for us to resize cluster, adding removing some nodes is easy.</p>
  
  <p>In apache hadoop, we can modify <code>slaves</code> file to change add or remove nodes. But I found <code>slaves</code> file in EMR contains just <code>localhost</code> and I can't find any other configuration that indicate where slaves are.</p>
  
  <p>How EMR add or remove nodes from the cluster without even restart process in Master node?</p>