Hadoop DataNodes trying to reconnect to itself.

[Binita Bharati <bi...@gmail.com>]

Hi ,

I am using Hadoop 2.7 on Ubuntu 14.04 cluster. I have 1 NamedNode (IP -
192.168.56.101, HostName - ubuntu) and 2 DataNode (IP - 192.168.56.102,
HostName - ubuntu2 and IP - 192.168.56.103, HostName - ubuntu3).

When I run :
$HADOOP_HOME/bin/hadoop fs -put /home/file.txt /user/user1

It fails with the below error:

=========================================

15/10/04 15:18:11 WARN hdfs.DFSClient: DataStreamer Exception

org.apache.hadoop.ipc.RemoteException(java.io.IOException): File
/user/hdfs1/1.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)

============================================

I see that in my DataNode logs , the DataNodes are trying to connect to
itself, instead of the NamedNode.

============================================

2015-10-04 13:42:14,498 INFO org.apache.hadoop.ipc.Client: Retrying connect
to server: ubuntu2/192.168.56.102:9000. Already tried 1 time(s); retry
policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000
MILLISECONDS)

==============================================

But, the entry in core-site.xml are identical for all 2 VMs. And the entry
points to the NamedNode only (hdfs at port 9000)

==============================================

*<configuration>*

*        <property>*

*                <name>fs.default.name <http://fs.default.name/></name>*

*                <value>hdfs://ubuntu:9000</value>*

*        </property>*

*</configuration>*

*==============================================*

Thanks

Binita