This is the log info: org.apache.hadoop.hdfs.server.datanode.DataNode: Failed to read expected encryption handshake from client at /127.0.0.1:53611. Perhaps the client is running an older version of Hadoop which does not support encryption
I have two more questions here. 1 what the client mean, it mean the application running on hdfs, how does it have a encryption? 2 I have turn off the encryption about data transfer, rpc protection, http protection by setting properties of hadoop.rpc.protection, dfs.encrypt.data.transfer and dfs.http.policy as false, why there is still encryption? Any clue will be appreciated.