Set up Hadoop 2.6 in Ubuntu. Based on http://codesfusion.blogspot.nl/2013/10/setup-hadoop-2x-220-on-ubuntu.html updated to 2.6

hadoop.sh

sudo apt-get install openjdk-7-jdk
java -version
# java version "1.7.0_25"
# OpenJDK Runtime Environment (IcedTea 2.3.12) (7u25-2.3.12-4ubuntu3)
# OpenJDK 64-Bit Server VM (build 23.7-b01, mixed mode)
cd /usr/lib/jvm
ln -s java-7-openjdk-amd64 jdk
 
sudo apt-get install openssh-server

sudo addgroup hadoop
sudo adduser --ingroup hadoop hduser
sudo adduser hduser sudo

sudo su hduser

ssh-keygen -t rsa -P ''
cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

ssh localhost

sudo tar vxzf hadoop-2.2.0.tar.gz -C /usr/local
cd /usr/local

sudo mv hadoop-2.2.0 hadoop
sudo chown -R hduser:hadoop hadoop

# paste following to the end of the BASHRC
 
#Hadoop variables
export JAVA_HOME=/usr/lib/jvm/jdk/
export HADOOP_INSTALL=/usr/local/hadoop
export PATH=$PATH:$HADOOP_INSTALL/bin
export PATH=$PATH:$HADOOP_INSTALL/sbin
export HADOOP_MAPRED_HOME=$HADOOP_INSTALL
export HADOOP_COMMON_HOME=$HADOOP_INSTALL
export HADOOP_HDFS_HOME=$HADOOP_INSTALL
export YARN_HOME=$HADOOP_INSTALL
###end of paste

cd /usr/local/hadoop/etc/hadoop
vi hadoop-env.sh
export JAVA_HOME=/usr/lib/jvm/jdk/

$ cd /usr/local/hadoop/etc/hadoop
$ vi core-site.xml
#Paste following between <configuration>
 
<property>
   <name>fs.default.name</name>
   <value>hdfs://localhost:9000</value>
</property>
 
 
$ vi yarn-site.xml
#Paste following between <configuration>
 
<property>
   <name>yarn.nodemanager.aux-services</name>
   <value>mapreduce_shuffle</value>
</property>
<property>
   <name>yarn.nodemanager.aux-services.mapreduce.shuffle.class</name>
   <value>org.apache.hadoop.mapred.ShuffleHandler</value>
</property>
 
 
mv mapred-site.xml.template mapred-site.xml
vi mapred-site.xml

<configuration>
<property>
   <name>mapreduce.framework.name</name>
   <value>yarn</value>
</property>
</configuration> 
 
cd ~
mkdir -p mydata/hdfs/namenode
mkdir -p mydata/hdfs/datanode
cd /usr/local/hadoop/etc/hadoop
vi hdfs-site.xml

<configuration>
<property>
   <name>dfs.replication</name>
   <value>1</value>
 </property>
 <property>
   <name>dfs.namenode.name.dir</name>
   <value>file:/home/hduser/mydata/hdfs/namenode</value>
 </property>
 <property>
   <name>dfs.datanode.data.dir</name>
   <value>file:/home/hduser/mydata/hdfs/datanode</value>
 </property>
</configuration>

hdfs namenode -format

# takes a while to start
start-dfs.sh

start-yarn.sh

cd /usr/local/hadoop

#run examples
hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-2.6.0.jar pi 2 5