title: httpfs error Operation category READ is not supported in state standby
body: <p>I am working on hadoop apache 2.7.1 and I have a cluster that consists of 3 nodes</p>
  
  <p>nn1<br>
  nn2<br>
  dn1</p>
  
  <p>nn1 is the dfs.default.name, so it is the master name node.</p>
  
  <p>I have installed httpfs and started it of course after restarting all the services. When nn1 is active and nn2 is standby I can send this request</p>
  
  <pre><code>http://nn1:14000/webhdfs/v1/aloosh/oula.txt?op=open&amp;user.name=root
  </code></pre>
  
  <p>from my browser and a dialog of <em>open or save for this file</em> appears, but when I kill the name node running on nn1 and start it again as normal then because of high availability nn1 becomes standby and nn2 becomes active.</p>
  
  <p>So here httpfs should work, even if nn1 becomes stand by, but sending the same request now </p>
  
  <pre><code>http://nn1:14000/webhdfs/v1/aloosh/oula.txt?op=open&amp;user.name=root
  </code></pre>
  
  <p>gives me the error </p>
  
  <pre><code>{"RemoteException":{"message":"Operation category READ is not supported in state standby","exception":"RemoteException","javaClassName":"org.apache.hadoop.ipc.RemoteException"}}
  </code></pre>
  
  <p>Shouldn't httpfs overcome nn1 standby status and bring the file? Is that because of a wrong configuration, or is there any other reason?</p>
  
  <p>My <code>core-site.xml</code> is </p>
  
  <pre><code>&lt;property&gt;
         &lt;name&gt;hadoop.proxyuser.root.hosts&lt;/name&gt;
                  &lt;value&gt;*&lt;/value&gt;
         &lt;/property&gt;
  
          &lt;property&gt;
                  &lt;name&gt;hadoop.proxyuser.root.groups&lt;/name&gt;
                  &lt;value&gt;*&lt;/value&gt;
          &lt;/property&gt;
  </code></pre>