Thank you very much, Piyush! I'll do as you say :DD Thanks a lot!! Thanks Smith :) hmm ... I see. ok :)
Please give me more guidance and suggestions if possible, dear experts! -Rita :)) On Sat, Aug 14, 2010 at 10:09 PM, smith jack <[email protected]> wrote: > that means you can only trace by log, > and not possible to debug hadoop using step debug, haha > distributed system always introduce extra complexity and confusing issues. > > 2010/8/15 Piyush Garg <[email protected]>: > > Hi Rita, > > > > You can put log4j logger debug statements in the code. log4j library is > > part of hadoop framework and there is already a log4j.properties file in > > hadoop conf directory and all the output logs are saved in hadoop logs > > directory. > > > > Thanks and Regards > > Piyush Garg > > > > > > On Sunday 15 August 2010 10:20 AM, Rita Liu wrote: > >> Thank you very much, Piyush! :) May I know more about how to use > "traces"? > >> > >> And -- yes, please teach me if possible, experts! :) > >> > >> Thanks a lot, > >> -Rita :)) > >> > >> On Sat, Aug 14, 2010 at 9:42 PM, Piyush Garg <[email protected]> > wrote: > >> > >> > >>> Hi Rita, > >>> > >>> I have just started to learn hadoop as well, I know there is a long way > >>> to go. > >>> I found some useful links which I am sharing with you. > >>> > >>> Hadoop Tutorial - YDN > >>> <http://developer.yahoo.com/hadoop/tutorial/index.html> excellent > >>> beginners tutorial and well organized. > >>> Running Hadoop On Ubuntu Linux (Single-Node Cluster) - Michael G. Noll > >>> < > >>> > http://www.michael-noll.com/wiki/Running_Hadoop_On_Ubuntu_Linux_%28Single-Node_Cluster%29 > >>> > >>>> > >>> Running_Hadoop_On_Ubuntu_Linux_(Multi-Node_Cluster) > >>> < > >>> > http://www.michael-noll.com/wiki/Running_Hadoop_On_Ubuntu_Linux_%28Multi-Node_Cluster%29 > >>> > >>>> > >>> The tutorial on the hadoop wiki > >>> <http://hadoop.apache.org/common/docs/r0.20.0/mapred_tutorial.html> is > >>> too much for a beginner. > >>> > >>> Debugger: > >>> I do not think you can easily do debugging using remote debugger. This > >>> is natural since hadoop is not sequential programming, it would be very > >>> difficult to debug its apps. > >>> The only way to debug is to use traces. > >>> > >>> I think you can learn how to setup multi-node cluster, but for practice > >>> session you can use single node setup. > >>> > >>> Lets see what the experts say. > >>> > >>> Thanks and Regards > >>> Piyush Garg > >>> > >>> > >>> On Sunday 15 August 2010 09:07 AM, Rita Liu wrote: > >>> > >>>> Hi! > >>>> > >>>> I am a total beginner, but I am very interested in hadoop. I've > already > >>>> downloaded hadoop 0.19.2 and run on Ubuntu in single-node mode. Now I > >>>> > >>> want > >>> > >>>> to do two things: > >>>> > >>>> 1. Explore how hadoop works internally with one of the example > >>>> > >>> applications > >>> > >>>> hadoop provides > >>>> 2. Write an application on my own > >>>> > >>>> Those two things bring me following questions: > >>>> > >>>> a. debugger? > >>>> I am stuck since I don't know how to "explore" hadoop. I used to trace > >>>> through the code using a debugger, but in this case, I don't know if > >>>> > >>> there > >>> > >>>> is a good debugger to use; or -- maybe a debugger is not necessary for > >>>> hadoop? If not, then how do you trace through the code to either debug > or > >>>> just gain an understanding about the system? May I know what you, > >>>> experienced experts, do? :) > >>>> > >>>> b. Where to run hadoop? > >>>> Also -- may I know where you run your hadoop? Do you run on linux, or > on > >>>> > >>> VM > >>> > >>>> -- in particular, Cloudera? I heard that Cloudera is good for writing > >>>> mapreduce applications with hadoop itself as a blackbox; is it true? > If > >>>> > >>> my > >>> > >>>> ultimate goal is to understand how hadoop works internally, would it > be > >>>> better if I directly run it on linux? > >>>> > >>>> c. Single-node or multi-node? > >>>> In the beginning (just like my case :p) would it be better to use > >>>> single-node or multi-node? If the latter is true, should I obtain more > >>>> machines, or should I use more virtual machines to create more nodes? > >>>> > >>>> As a newbie, I am sorry for all those basic (and silly, I know :$) > >>>> questions. If possible, please help me out? Any suggestion or advice > will > >>>> > >>> be > >>> > >>>> greatly appreciated. Thank you very much! > >>>> > >>>> Best, > >>>> Rita :) > >>>> > >>>> P.S. If my questions are not suitable for this mailing-list, please > let > >>>> > >>> me > >>> > >>>> apologize, and then, could you please direct me to other > mailing-lists? > >>>> Sorry, and thanks a lot! :) > >>>> > >>>> > >>>> > >>> > >> > > >
