How to debug hadoop mapreduce jobs from eclipse?

Question

I\'m running hadoop in a single-machine, local-only setup, and I\'m looking for a nice, painless way to debug mappers and reducers in eclipse. Eclipse has no probl

Answer 1

Besides the recommended MRUnit I like to debug with eclipse as well. I have a main program. It instantiates a Configuration and executes the MapReduce job directly. I just debug with standard eclipse Debug configurations. Since I include hadoop jars in my mvn spec, I have all hadoop per se in my class path and I have no need to run it against my installed hadoop. I always test with small data sets in local directories to make things easy. The defaults for the configuration behaves as a stand alone hadoop (file system is available)