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Access to HDFS files from all computers of a cluster

Question asked by vladdv on Feb 12, 2013
Latest reply on Apr 27, 2015 by snayeem
My hadoop the program originally was launched in a local mode, and now my purpose became start in completely distributed mode. For this purpose it is necessary to provide access to the files which reading is executed in the reducer and mapper functions, from all computers of a cluster and therefore I asked a question on http://answers.mapr.com/questions/4444/syntax-of-option-files-in-hadoop-script (also as it will be not known on what computer to be executed the mapper function (mapper from logic of the program there will be only one and the program will be launched only with one mapper), it is necessary to provide also access on all cluster to the file arriving on an input of the mapper function). In this regard I had a question: Whether it is possible to use hdfs-files directly: that is to copy beforehand files from file system of Linux in file system of HDFS (thereby as I assume, these files become available on all computers of a cluster if it not so, correct please) and then to use HDFS Java API for reading these files, in the reducer and mapper functions which are executing on computers of a cluster?
If on this question the response the positive, give please a copying example from file system of Linux in file system of HDFS and reading these files in java to the program by means of HDFS Java API.

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