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From Mike Spreitzer <mspre...@us.ibm.com>
Subject Re: Hadoop not working after replacing hadoop-core.jar with hadoop-core-append.jar
Date Fri, 10 Jun 2011 18:43:33 GMT
Thanks for the clarification.  How about the following update to the text? 
 Where it currently says

<para>Because HBase depends on Hadoop, it bundles an instance of the 240 
Hadoop jar under its <filename>lib</filename> directory. The bundled 241 
Hadoop was made ...

we clarify that the bundled JAR is ONLY for use in standalone mode, 
perhaps like this:

<para>Because HBase depends on Hadoop, it bundles an instance of the 240 
Hadoop jar under its <filename>lib</filename> directory --- but this is 
<emphasis>only</emphasis> for use in standalone mode. The bundled 241 
Hadoop was made ...

Also, why does this text say 240 at first and then 241?  And why not 
explicitly give the name of the JAR file in question, which is 

Mike Spreitzer

From:   Stack <stack@duboce.net>
To:     user@hbase.apache.org
Date:   06/10/2011 02:33 PM
Subject:        Re: Hadoop not working after replacing hadoop-core.jar 
with hadoop-core-append.jar
Sent by:        saint.ack@gmail.com

On Fri, Jun 10, 2011 at 10:06 AM, Mike Spreitzer <mspreitz@us.ibm.com> 
> stack <saint.ack@gmail.com> wrote on 06/06/2011 10:57:50 PM:
>> From: stack <saint.ack@gmail.com>
> Let me see if I have got this straight.  Hadoop branch-0.20-append is 
> an immutable thing, it has evolved a little over time.


> The hadoop-core.jar that is included in the HBase distribution was built 
> some version of branch-0.20-append.  If my own Hadoop cluster is EXACTLY
> the same version of branch-0.20-append then I do not need to replace any
> files anywhere.  However, since nobody is telling me the version of
> branch-0.20-append from which HBase's hadoop-core.jar was built,

It says so in the jar name.  The jar is called >0.20-append-r1056497.
The latter is the svn revision we built the jar from.

>  I can not
> in any case or way be confident that my cluster is running EXACTLY the
> same version even if it is branch-0.20-append.

Not true.

> So the net result is that
> in all distributed cases (except when I import pre-built Hadoop+HBase 
> Cloudera or elsewhere) I have to build branch-0.20-append and copy it's
> core JAR into my HBase lib.  Have I got this right?  The book still does
> not say that clearly.  In fact, the book still points to my old email
> saying I did it the other way around.  Your reply above clearly seems to
> imply that I need to replace HBase's hadoop core JAR only in some
> distributed cases.  Yet the rest of the email conversation on this point
> seems to have settled that HBase's hadoop core JAR needs to be replaced 
> all distributed cases.

My reading of the text is that the jar should always be replaced.  I
added the callout that cited your old mail thread because I thought it
might be of interest.  It seems to have only made confusion so in the
edit I posted above (for review), I'd completely removed it.

The edit has not been pushed to the website.  I thought I'd get a bit
of input on it first.  Here is the link again:


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