Right, thanks.  I had seen some of those resources but I'll definitely go over 
them in greater detail.  To be honest, I was actually a little unclear about 
the backward compatibility.  On the one hand, it is clearly documented that old 
MR programs should work in YARN, but on the other hand YARN seems to infer 
radical changes to the allocation of resources for a job (such as the 
all-important alleviation of assigning slots to mappers and reducers).  That 
had me thinking that there must be crucial differences in how a job is 
organized and submitted, regardless of any notion of backward compatibility.

I'll go over the various documentation again.  Thanks for the references.

Cheers!

On May 23, 2012, at 19:27 , Arun C Murthy wrote:

> Keith,
> 
>  Happy to help.
> 
>  When you mean .23 API, do you mean how to write your own applications on top 
> of YARN?
> 
>  If so, you can start with hadoop-2 release docs:
>  
> http://hadoop.apache.org/common/docs/r2.0.0-alpha/hadoop-yarn/hadoop-yarn-site/WritingYarnApplications.html
> 
>  There is also an example application (DistributedShell) you can look at for 
> a simpler usage of YARN apis:
> http://svn.apache.org/viewvc/hadoop/common/branches/branch-2/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-applications/hadoop-yarn-applications-distributedshell/src/main/java/org/apache/hadoop/yarn/applications/distributedshell/
> 
>  As you are probably aware, MapReduce applications itself don't need to 
> change when you move to using hadoop-2.
> 
> thanks,
> Arun
> 
> On May 23, 2012, at 3:18 PM, Keith Wiley wrote:
> 
>> I have already preordered the third edition of Tom's book (obviously, I 
>> don't have it yet since it won't be published until the end of the month), 
>> but aside from that, I'm looking for good resources for learning how to 
>> program to the .23 API.  I have found several websites and articles that 
>> discuss the philosophical differences between .20 and .23 but I'm looking 
>> for teaching/learning resources for getting into the guts and actually 
>> programming the thing.  I'm pretty competent at .20 so I'm not looking for 
>> starter-level hadoop stuff.  Rather, I'm looking for transitional resources 
>> to learn the specifics of the new design.
>> 
>> Any ideas?  How are people vetted on the older versions of hadoop learning 
>> the way of the YARN?
>> 
>> Thanks.


________________________________________________________________________________
Keith Wiley     kwi...@keithwiley.com     keithwiley.com    music.keithwiley.com

"The easy confidence with which I know another man's religion is folly teaches
me to suspect that my own is also."
                                           --  Mark Twain
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