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From "Habermaas, William" <William.Haberm...@fatwire.com>
Subject RE: Bad connection to FS. command aborted
Date Wed, 11 May 2011 13:43:17 GMT
If the hadoop script is picking up a different hadoop-core jar then the classes that ipc to
the NN will be using a different version. 


-----Original Message-----
From: Matthew John [mailto:tmatthewjohn1988@gmail.com] 
Sent: Wednesday, May 11, 2011 9:41 AM
To: common-user@hadoop.apache.org
Subject: Re: Bad connection to FS. command aborted

I did a "ant jar" after modifying two files in the mapred module. This, from
what I understand, creates a hadoop-*-core.jar in the build folder. Now I
assume that will be used henceforth for any execution. So how can this be a
problem if I am running a single-node cluster. Version mismatch with whom ?

On Wed, May 11, 2011 at 7:07 PM, Habermaas, William <
William.Habermaas@fatwire.com> wrote:

> The Hadoop IPCs are version specific.  That is done to prevent an older
> version from talking to a newer one.  Even if nothing has changed in the
> internal protocols the version check is enforced.  Make sure the new
> hadoop-core.jar from your modification is on the classpath used by the
> hadoop shell script.
> Bill
> -----Original Message-----
> From: Matthew John [mailto:tmatthewjohn1988@gmail.com]
> Sent: Wednesday, May 11, 2011 9:27 AM
> To: common-user
> Subject: Bad connection to FS. command aborted
> Hi all!
> I have been trying to figure out why I m getting this error!
> All that I did was :
> 1) Use a single node cluster
> 2) Made some modifications in the core (in some MapRed modules).
> Successfully compiled it
> 3) Tried bin/start-dfs.sh alone.
> All the required daemons (NN and DN) are up.
> The NameNode and DataNode logs are nt showing any errors/exceptions.
> Only interesting thing I found was :
> *WARN org.apache.hadoop.ipc.Server: Incorrect header or version mismatch
> from got version 94 expected version 3  *
> in the NameNode logs.
> Someone please help me out of this!
> Matthew
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