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Hadoop's Distributed Cache is a mechanism to distribute files into the working directory of each map and reduce task. The origin of these files is HDFS. Pentaho MapReduce will automatically configure the job to use a Kettle environment from HDFS (configured via pmr.kettle.installation.id, see Configuration options). If the desired Kettle environment does not exist, Pentaho MapReduce will take care of "installing" it in HDFS before executing the job.
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