On all nodes:
For RHEL/CentOS:
yum upgrade hadoop\*
For SLES:
zypper update hadoop\*
Start HDFS.
Start NameNode. On the NameNode host machine, execute the following command:
sudo su -l hdfs -c "/usr/lib/hadoop/bin/hadoop-daemon.sh start namenode"Start Secondary NameNode. On the Secondary NameNode host machine, execute the following command:
sudo su -l hdfs -c "/usr/lib/hadoop/bin/hadoop-daemon.sh start secondarynamenode"Start DataNodes. On all the DataNodes, execute the following command:
sudo su -l hdfs -c \"/usr/lib/hadoop/bin/hadoop-daemon.sh start datanode\"Execute the following on the NameNode machine:
hadoop dfsadmin -safemode wait
Start MapReduce.
Start JobTracker. On the JobTracker host machine, execute the following command:
sudo su -l mapred -c "/usr/lib/hadoop/bin/hadoop-daemon.sh start jobtracker"Start JobHistory Server. On the JobHistory Server host machine, execute the following command:
sudo su -l mapred -c "/usr/lib/hadoop/bin/hadoop-daemon.sh start historyserver"Start all TaskTrackers. On all the TaskTrackers, execute the following command:
sudo su -l mapred -c \"/usr/lib/hadoop/bin/hadoop-daemon.sh start tasktracker\"

