Thanks Steve. It worked. On Sun, Mar 27, 2011 at 2:08 PM, Steve Loughran <[email protected]> wrote:
> On 25/03/2011 14:10, bikash sharma wrote: > >> Hi, >> For my research project, I need to add a couple of functions in >> JobTracker.java source file to include additional information about >> TaskTrackers resource usage through heartbeat messages. I made those >> changes >> to JobTracker.java file. However, I am not very clear how to see these >> effects. I mean what are the next steps in terms of building the entire >> Hadoop code base, using the built distribution and installing it again in >> the cluster, etc? >> > > If you are working with the Job Tracker you only need to rebuild the > mapreduce JARs and push the new JAR out to the Job Tracker server, restart > that process. > > For more safety, put the same JAR on all the task trackers and shut down > HDFS before the updates, but that's potentially overkil > > > Any elaborate updates on these will be very useful since I do not have >> much >> experience in doing modifications to Hadoop like huge code base and >> observing the effects of these changes. >> > > I'd recommend getting everything working on a local machine single VM (the > MiniMRCluster class helps), then move to multiple VMs and finally, if the > code looks good, a real cluster with data you don't value. > > -stee >
