Hadoop setup step from zero to HA mode
1,#Setup root@
关闭mail服务（四台主机）
chkconfig sendmail off
修改主机名（四台主机）
vi /etc/sysconfig/network
hostname serverX
修改IP（四台主机）
vi /etc/sysconfig/network-scripts/ifcfg-eth0
BOOTPROTO=static
IPADDR=192.168.7.10X
ONBOOT=yes
service network restart
修改hosts文件，IP地址与主机名对应关系
vi /etc/hosts
127.0.0.1 localhost.localdomain localhost
::1 localhost6.localdomain6 localhost6
192.168.7.101 server1
192.168.7.102 server2
192.168.7.103 server3
192.168.7.104 server4
删除用户
userdel -r hadoop
1、创建用户（四台主机）
useradd hadoop
passwd hadoop
2、分别修改hosts文件（四台主机）
vi /etc/hosts
去掉127.0.0.1后面的主机名（localhost.localdomain localhost保留）
添加
192.168.7.101 server1
192.168.7.102 server2
192.168.7.103 server3
192.168.7.104 server4
配置SSH
server1: hadoop:
ssh-keygen -t rsa
cd .ssh
cp id_rsa.pub authorized_keys
server2、3、4: hadoop:
cd
mkdir .ssh
chmod 700 /home/hadoop/.ssh/
server1:
hadoop:
scp id_rsa.pub hadoop@Server2:/home/hadoop/.ssh/authorized_keys
scp id_rsa.pub hadoop@Server3:/home/hadoop/.ssh/authorized_keys
scp id_rsa.pub hadoop@Server4:/home/hadoop/.ssh/authorized_keys
