爲什麼我的datanode在hadoop集羣上運行，但我仍然無法將文件放入hdfs？

Question

當我在NameNode的JPS

stillily@localhost:~$ jps 
3669 SecondaryNameNode 
3830 ResourceManager 
3447 NameNode 
4362 Jps 

當我的DataNode

stillily@localhost:~$ jps 
3574 Jps 
3417 NodeManager 
3292 DataNode 

JPS但是當我把一個文件

stillily@localhost:~$ hadoop fs -put txt hdfs://hadoop:9000/txt 
15/07/21 22:08:32 WARN hdfs.DFSClient: DataStreamer Exception 
org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /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. 
at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.chooseTarget4NewBlock(BlockManager.java:1550) 
at 
....... 
put: File /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. 

而且我注意到，沒有 「版本」 文件在datanode機器中，但無論我運行多少次「hadoop namenode -format」，都會創建版本文件。

BTW ubuntu。

Answer 1

現在我知道原因是VM的IP已經改變。我只是修改namenode中的/ etc/hosts，但沒有修改datanode中的那個。