It is a problem of environmental variables setup. Apparently, I didnt find one which can work until NOW. I was trying on 2.6.4. Here is what we should do

export HADOOP_HOME=/home/centos/HADOOP/hadoop-2.6.4
export HADOOP_INSTALL=$HADOOP_HOME
export HADOOP_MAPRED_HOME=$HADOOP_HOME
export HADOOP_COMMON_HOME=$HADOOP_HOME
export HADOOP_HDFS_HOME=$HADOOP_HOME
export YARN_HOME=$HADOOP_HOME
export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native
export PATH=$PATH:$HADOOP_HOME/sbin:$HADOOP_HOME/bin
export HADOOP_CONF_DIR=$HADOOP_HOME
export HADOOP_PREFIX=$HADOOP_HOME
export HADOOP_LIBEXEC_DIR=$HADOOP_HOME/libexec
export JAVA_LIBRARY_PATH=$HADOOP_HOME/lib/native:$JAVA_LIBRARY_PATH
export HADOOP_CONF_DIR=$HADOOP_PREFIX/etc/hadoop

Add these into your .bashrc and dont forget to do

source ~/.bashrc

I think your problem will be solved as was mine.

You probably did not follow the instructions correctly. Here are some things to try and help us / you diagnose this:

• In the shell that you ran hadoop version, run export and show us the list of relevant environment variables.

• Show us what you put in the /usr/local/hadoop/etc/hadoop/hadoop-env.sh file.

• If neither of the above gives you / us any clues, then find and use a text editor to (temporarily) modify the hadoop wrapper shell script. Add the line "set -xv" somewhere near the beginning. Then run hadoop version, and show us what it produces.

Adding this line to ~/.bash_profile worked for me.

export HADOOP_PREFIX=/<where ever you install hadoop>/hadoop

So just:

1. $ sudo open ~/.bash_profile then add the aforesaid line
2. $ source ~/.bash_profile

Hope this helps (: