Hello Everybody,
I have a doubt in a map reduce program and I would appreciate
any
help. I run the program using the command bin/hadoop jar HomeWork.jar prg1 input
output. Ideally from within prg1, I want to sequentially launch 10 map- reduce
tasks. I want to store the output of all these map reduce tasks in some file.
Currently I have kept the input format and output format of the jobs as
TextInputFormat and TextOutputFormat respectively. Now I have the following
questions.
1. When I run more than 1 task from the same program, the output file of all the
tasks is same. The framework does not allows the 2 map reduce task to have the
same output file as task 1.
2. Before the 2 task launches I also get this error
Cannot initialize JVM Metrics with processName=JobTracker, sessionId= - already
initialized
3. When the 2 map reduce tasks writes its output to file "output", wont the
previous content of this file get over written ?
Thank You
Abhishek Agrawal
SUNY- Buffalo
(716-435-7122)
