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MapReduce Tutorial : If things go wrong
A lot can go wrong in the process of submitting and running Hadoop job:
Hadoop::Runner.pmmodule not found: The Perl Hadoop package is not configured, see Setting the environment.ipc.Client: Retrying connect to server: IP_ADDRESS:PORT. Already tried ? time(s): The jobtracker cannot be contacted. If using-jt jobtracker:portflag, check, that the jobtracker address is correct.