title: No active nodes in Hadoop cluster
body: <p>I set up Hadoop 2.6.0 with 1 master and 2 slaves according to <a href="http://pingax.com/install-apache-hadoop-ubuntu-cluster-setup/" rel="nofollow">How to install Apache Hadoop 2.6.0 in Ubuntu (Multi node/Cluster setup)</a>. After all I checked jps on master and slaves, all looked good: NameNode, SecondaryNameNode, ResourceManager on master; and DataNode, NodeManager on slaves. But when I browsed to hadoopmaster:8088, there was 0 active nodes. Also when I run</p>
  
  <pre><code>hadoop fs -put ~/h-localdata/* /input/
  </code></pre>
  
  <p>It showed this error:</p>
  
  <pre><code>put: File /input-01/h-localdata/README.txt._COPYING_ could only be replicated to 0 nodes instead of minReplication (=1).  There are 0 datanode(s) running and no node(s) are excluded in this operation.
  </code></pre>
  
  <p>Please help me solve this!</p>