title: Hadoop Ports Clarification
body: <p>I am learning hadoop and bit confused about the default ports and the locations.</p>
  
  <p>When I hit the URL: localhost:50070 gives a result for the hdfs info.
  In hadoop docs following are some of the ports mentioned.</p>
  
  <p><strong>hdfs-default.xml</strong>  </p>
  
  <pre><code>dfs.datanode.http.address   0.0.0.0:50075 
  dfs.datanode.address     0.0.0.0:50010
  dfs.namenode.http-address    0.0.0.0:50070
  dfs.namenode.backup.http-address    0.0.0.0:50105
  </code></pre>
  
  <p><strong>mapred-default.xml</strong></p>
  
  <pre><code>mapreduce.jobtracker.http.address   0.0.0.0:50030
  mapreduce.tasktracker.http.address  0.0.0.0:50060
  </code></pre>
  
  <p><strong>yarn-default.xml</strong></p>
  
  <pre><code>yarn.resourcemanager.address     ${yarn.resourcemanager.hostname}:8032
  yarn.resourcemanager.webapp.address  ${yarn.resourcemanager.hostname}:8088
  </code></pre>
  
  <p>Now while configuring Hadoop 2 in my machine 
  I did :
  $ cd /usr/local/hadoop/etc/hadoop
  $ vi core-site.xml</p>
  
  <pre><code>&lt;property&gt;
     &lt;name&gt;fs.default.name&lt;/name&gt;
     &lt;value&gt;hdfs://localhost:9000&lt;/value&gt;
  &lt;/property&gt;
  </code></pre>
  
  <p>Question:
  There are so many ports mentioned in the default and other xml in the docs ....</p>
  
  <p>1) localhost:50070 only returns some meaning full data (hdfs health) what about the other ports. Others just dont return any information  ?</p>
  
  <p>2) in yarn-default.xml both are resource manager ports difference is one is webapp port. only the when I hit localhost:8088 in browser it gives the cluster(single node in this case ) information. Then what is the port 8083? In a sample code I see 8083 is the RM port. Not clear to me. Can someone please explain</p>
  
  <p>3)I changed the hdfs port to 9000 is that standard? </p>
  
  <p>4)How to see the appmaster, jobtracker, tasktracker ports </p>
  
  <p>5) I thought in yarn hadoop 2 there is no jobtracker and tasktracker then what are the purpose of these ports ? </p>
  
  <p>I am having nightmare with these basic questions... </p>
  
  <p>Thanks,
  Amit</p>