title: Hadoop webuser: No such user
body: <p>While running a hadoop multi-node cluster , i got below error message on my master logs , can some advise what to do..? do i need to create a new user or can i gave my existing Machine user name over here </p>
  
  <blockquote>
    <p>2013-07-25 19:41:11,765 WARN
    org.apache.hadoop.security.UserGroupInformation: No groups available
    for user webuser 2013-07-25 19:41:11,778 WARN
    org.apache.hadoop.security.ShellBasedUnixGroupsMapping: got exception
    trying to get groups for user webuser
    org.apache.hadoop.util.Shell$ExitCodeException: id: webuser: No such
    user</p>
  </blockquote>
  
  <p>hdfs-site.xml file</p>
  
  <pre><code>&lt;configuration&gt;
  &lt;property&gt;
    &lt;name&gt;dfs.replication&lt;/name&gt;
    &lt;value&gt;2&lt;/value&gt;
    &lt;description&gt;Default block replication.
    The actual number of replications can be specified when the file is created.
    The default is used if replication is not specified in create time.
    &lt;/description&gt;
  &lt;/property&gt;
  
  &lt;/configuration&gt;
  </code></pre>
  
  <p>core-site.xml</p>
  
  <pre><code>&lt;configuration&gt;
  &lt;property&gt;
    &lt;name&gt;fs.default.name&lt;/name&gt;
    &lt;value&gt;hdfs://master:54310&lt;/value&gt;
    &lt;description&gt;The name of the default file system.  A URI whose
    scheme and authority determine the FileSystem implementation.  The
    uri's scheme determines the config property (fs.SCHEME.impl) naming
    the FileSystem implementation class.  The uri's authority is used to
    determine the host, port, etc. for a filesystem.&lt;/description&gt;
  &lt;/property&gt;
  
  &lt;/configuration&gt;
  </code></pre>
  
  <p>mapred-site.xml</p>
  
  <pre><code>&lt;configuration&gt;
  &lt;property&gt;
    &lt;name&gt;mapred.job.tracker&lt;/name&gt;
    &lt;value&gt;master:54311&lt;/value&gt;
    &lt;description&gt;The host and port that the MapReduce job tracker runs
    at.  If "local", then jobs are run in-process as a single map
    and reduce task.
    &lt;/description&gt;
  &lt;/property&gt;
  
  &lt;/configuration&gt;
  </code></pre>
  
  <p>i followed <a href="http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-multi-node-cluster/" rel="nofollow">http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-multi-node-cluster/</a> . </p>
  
  <p>Hadoop 1.2.0
  jetty-6.1.26</p>
  
  <p>After adding my hdfs-site.xml looks </p>
  
  <pre><code>&lt;configuration&gt;
  &lt;property&gt;
    &lt;name&gt;dfs.replication&lt;/name&gt;
      &lt;value&gt;2&lt;/value&gt;
        &lt;description&gt;Default block replication.
          The actual number of replications can be specified when the file is created.
            The default is used if replication is not specified in create time.
   &lt;/description&gt;
  &lt;/property&gt;
  &lt;property&gt;
  &lt;name&gt;dfs.web.ugi&lt;/name&gt;
  &lt;value&gt;hduser,hadoop&lt;/value&gt;
  &lt;/property&gt;
  &lt;/configuration&gt;
  </code></pre>