title: Namenode recovery, How does namenode recovery works?
body: <p>In <code>hadoop</code> ecosystem we have <code>NameNode</code> and <code>SecondaryNameNode</code>, <code>NameNode</code> is responsible to managing all data available in cluster, So my question is when <code>NameNode</code> goes down how ecosystem replace and recover it with other <code>NameNode</code>?</p>