title: HDFS_NAMENODE_USER, HDFS_DATANODE_USER & HDFS_SECONDARYNAMENODE_USER not defined
body: <p>I am new to hadoop.<br>
  I'm trying to install hadoop in my laptop in Pseudo-Distributed mode.<br>
  I am running it with root user, but I'm getting the error below.</p>
  
  <pre><code>root@debdutta-Lenovo-G50-80:~# $HADOOP_PREFIX/sbin/start-dfs.sh
  WARNING: HADOOP_PREFIX has been replaced by HADOOP_HOME. Using value of HADOOP_PREFIX.
  Starting namenodes on [localhost]
  ERROR: Attempting to operate on hdfs namenode as root
  ERROR: but there is no HDFS_NAMENODE_USER defined. 
  Aborting operation.
  Starting datanodes
  ERROR: Attempting to operate on hdfs datanode as root
  ERROR: but there is no HDFS_DATANODE_USER defined. 
  Aborting operation.
  Starting secondary namenodes [debdutta-Lenovo-G50-80]
  ERROR: Attempting to operate on hdfs secondarynamenode as root
  ERROR: but there is no HDFS_SECONDARYNAMENODE_USER defined. Aborting operation.
  WARNING: HADOOP_PREFIX has been replaced by  HADOOP_HOME. Using value of HADOOP_PREFIX.
  </code></pre>
  
  <p>Also, I have to run hadoop in root user as hadoop is not able to access ssh service with other user.<br>
  How to fix the same? </p>