If that's the case, you may be able to fix that by adding the
following property to your hdfs-site.xml:

dfs.client.use.datanode.hostname = true

It should cause the hostnames of the data nodes to be returned to the
client, rather than private/inaccessible IPs.

Regards,
Matt


On Thu, Apr 19, 2018 at 8:22 AM, Bryan Bende <[email protected]> wrote:
> Hello,
>
> I have no idea how AWS works, but most likely what is happening is the
> Hadoop client in NiFi asks the name node to write a file, and the name
> node then responds with the data nodes to write to, but it is
> responding with the private IPs/hostnames of the data nodes which you
> can't reach from your windows machines.
>
> You would probably have the same problem if you tried installing the
> hadoop client on your windows machine and issue commands like "hadoop
> fs -ls /".
>
> -Bryan
>
>
> On Thu, Apr 19, 2018 at 1:55 AM, Sudheer Nulu <[email protected]> wrote:
>> Hi Team,
>>
>>
>>
>> I have recently started exploring Apache nifi to implement in our upcoming
>> projects.
>>
>>
>>
>> The issue is:
>>
>>
>>
>> I have nifi installed on my windows machine to transfer the data from oracle
>> database to aws instance hdfs layer by using putHDFS. files are transferred
>> to hdfs with 0 Bytes of memory.(Attached the snapshot for reference)
>>
>>
>>
>> I was able to place files using putsftp in aws instance without any
>> issue,but failed to do it in hdfs layer.
>>
>>
>>
>>
>>
>> In logs I could see this:
>>
>>
>>
>> <logs>
>>
>> WARN [Thread-5441] org.apache.hadoop.hdfs.DFSClient DataStreamer Exception
>> java.nio.channels.UnresolvedAddressException: null
>>
>> at sun.nio.ch.Net.checkAddress(Unknown Source) at
>> sun.nio.ch.SocketChannelImpl.connect(Unknown Source) at
>> org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:192)
>>
>> </logs>
>>
>>
>>
>> Procedure followed:
>>
>> I have copied the hdfs-site.xml and core-site.xml from aws instance and
>> replaced all private hostname with public hostname as I cannot communicate
>> with private DNS,then I provided those two files as inputs  to apache nifi
>> configuration.
>>
>>
>>
>> The hdfs layer has full permissions to write to it.
>>
>>
>>
>> Could someone help on this as I have struck at this point from longtime,
>> made many changes in hosts file for resolving hostname issue.
>>
>>
>>
>> Regards,
>>
>> Sudheer Nulu
>>
>>
>>
>>
>>
>>

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