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From Rakesh Radhakrishnan <rake...@apache.org>
Subject Re: Start client side daemon
Date Fri, 22 Jul 2016 15:43:51 GMT
Sorry, could you please tell me, what do you meant by "located" ?

Like I mentioned earlier, user applications will talk to the HDFS via
clients. For example, operations like create/open/write/read/delete files
etc via client.

Thanks,
Rakesh


On Fri, Jul 22, 2016 at 8:38 PM, Kun Ren <ren.hdfs@gmail.com> wrote:

> Thanks for your reply. So The clients can be located at any machine that
> has the HDFS client library, correct?
>
> On Fri, Jul 22, 2016 at 10:50 AM, Rakesh Radhakrishnan <rakeshr@apache.org
> > wrote:
>
>> Hi Kun,
>>
>> HDFS won't start any client side object(for example,
>> DistributedFileSystem). I can say, HDFS Client -> user applications access
>> the file system using the HDFS client, a library that exports the HDFS file
>> system interface. Perhaps, you can visit api docs,
>> https://hadoop.apache.org/docs/r2.6.1/api/org/apache/hadoop/fs/FileSystem.html
>> .
>>
>> Namenode has RPC server that listens to requests from data nodes,
>> clients. Datanode has RPC Server which will be used for inter data node
>> communications. I think, its worth reading the following to get more
>> information.
>> https://en.wikipedia.org/wiki/Apache_Hadoop
>>
>> https://hadoop.apache.org/docs/r2.7.2/hadoop-project-dist/hadoop-hdfs/HdfsDesign.html#The_Communication_Protocols
>>
>> Regards,
>> Rakesh
>> Intel
>>
>> On Fri, Jul 22, 2016 at 7:21 PM, Kun Ren <ren.hdfs@gmail.com> wrote:
>>
>>> Hi Genius,
>>>
>>> I understand that we use the command to start namenode and datanode. But
>>> I don't know how HDFS starts client side and creates the Client side
>>> object(Like DistributedFileSystem), and client side RPC server? Could you
>>> please point it out how HDFS start the client side dameon?
>>> If the client side uses the same RPC server with server side, Can I
>>> understand that the client side has to be located at either Namenode or
>>> Datanode?
>>>
>>> Thanks so much.
>>> Kun
>>>
>>
>>
>

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