我试图把一个文件放入hdfs使用ssh从我的客户端pc到namenode服务器。有两台机器：一个namenode和一个datanode。这是我正在尝试的命令；

$ bin/hadoop fs -fs hdfs://MY_IP:MY_PORT -put example.txt example.txt

但它抛出了一个例外。日志上说；

2013-05-23 09:25:31,808 ERROR org.apache.hadoop.security.UserGroupInformation: PriviledgedActionException as:_my_user_name_ cause:java.io.IOException: Unknown protocol to DataNode: org.apache.hadoop.hdfs.protocol.ClientProtocol
2013-05-23 09:25:31,808 INFO org.apache.hadoop.ipc.Server: IPC Server handler 1 on _my_port_, call getProtocolVersion(org.apache.hadoop.hdfs.protocol.ClientProtocol, 61) from _ip_:_port_: error: java.io.IOException: Unknown protocol to DataNode: org.apache.hadoop.hdfs.protocol.ClientProtocol
java.io.IOException: Unknown protocol to DataNode: org.apache.hadoop.hdfs.protocol.ClientProtocol
    at org.apache.hadoop.hdfs.server.datanode.DataNode.getProtocolVersion(DataNode.java:1759)
    at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:563)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1388)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1384)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:415)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
    at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1382)

有什么问题吗？谢谢