一、在Ubuntu下创建hadoop用户组合hadoop用户
1、创建hadoop用户组
addgroup hadoop
2、创建hadoop用户
adduser -ingroup hadoop hadoop
3、为hadoop用户添加权限
vim /etc/sudoers
4、切换到hadoop用户
su - hadoop
二、ssh安装与设置
1、安装ssh
sudo apt-get install openssh-server
2、启动服务
sudo /etc/init.d/ssh start
3、查看启动
ps -e | grep ssh
4、设置免密码登录，生成私钥与公钥
ssh-keygen -t rsa -P ""
此时会在／home／hadoop/.ssh下生成两个文件：id_rsa和id_rsa.pub，前者为私钥，后者为公钥。
将公钥追加到authorized_keys中，它用户保存所有允许以当前用户身份登录到ssh客户端用户的公钥内容。
cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
5、ssh登录
ssh localhost
6、退出登录
exit
三、安装java环境
1、安装java
sudo apt-get install openjdk-7-jdk
2、查看java版本
java -version
3、查看java安装路径
update-alternative --config java
四、安装hadoop2.7.1
1、下载hadoop2.7.1.tar.gz
2、解压：sudo tar xzf hadoop-2.7.1.tar.gz
3、复制到：sudo mv hadoop-2.7.1 /usr/local/hadoop
4、权限设置：sudo chmod 774 /usr/local/hadoop
5、配置.bashrc文件
#HADOOP VARIABLES START
export JAVA_HOME=/usr/lib/jvm/java--openjdk-amd64
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
export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_INSTALL/lib/native
export HADOOP_OPTS="-Djava.library.path=$HADOOP_INSTALL/lib"
#HADOOP VARIABLES END
6、环境变量生效
source ~/.bashrc
7、编辑/usr/local/hadoop/etc/hadoop/hadoop-env.sh
五、验证测试
1、/usr/local/hadoop路径下创建input文件夹
2、拷贝README.txt到input
3、执行WordCount
bin/hadoop jar share/hadoop/mapreduce/sources/hadoop-mapreduce-examples-2.4.0-sources.jar org.apache.hadoop.examples.WordCount input output
六、结果演示