1.安装JDK
1.1、卸载系统自带OPEN-JDK（所有节点）
执行以下命令查看系统中有哪些OpenJk相关包：
rpm -qa | grep java
其中有如下包必须卸载
rpm -e --nodeps java-1.5.0-gcj-1.5.0.0-29.1.el6.x86_64
rpm -e --nodeps java-1.6.0-openjdk-1.6.0.0-1.66.1.13.0.el6.x86_64
rpm -e --nodeps java-1.6.0-openjdk-devel-1.6.0.0-1.66.1.13.0.el6.x86_64
1.2.下载安装 jdk-8u121-linux-x64.rpm
安装jdk
chmod +x jdk-8u121-linux-x86.rpm
rpm -ivh jkd-8u121-linux-86.rpm
1.3.配置环境变量
[root@iZbp1barmvtqfdn6lceoyxZ tmp]# vi /etc/profile
追加配置：
export JAVA_HOME=/usr/java/jdk1.8.0_121
export JRE_HOME=$JAVA_HOME/jre
export PATH=$JAVA_HOME/bin:$PATH
保存配置文件source /etc/profile激活配置,不然重开机后可能没有成功修改配置文件
2.修改swappiness配置文件
执行命令cat /proc/sys/vm/swappiness 一般情况下都是60
vi /etc/sysctl.conf 添加 vm.swappiness=0 保存退出；重启后再查看就回是0
操作这个是为了最后一步安装检查集群节点时出现警告
具体原理请看http://blog.csdn.net/wulantian/article/details/36184943
3.关闭防火墙（所有节点）
centos7之前
临时关闭：service iptables stop
永久关闭：chkconfig iptables off
查看关闭状况：service iptables status
centos从7开始默认用的是firewalld，这个是基于iptables的，虽然有iptables的核心，但是iptables的服务是没安装的。所以你只要停止firewalld服务即可：
sudo systemctl stop firewalld.service && sudo systemctl disable firewalld.service
4.关闭SELINUX关、配置umask值
vi /etc/selinux/config
setenforce 0 （临时生效）修改 SELINUX=disabled （重启后永久生效）
查看SELINUX状态
若SELinux status 为disabled 即为关闭
echo umask 0022 >> /etc/profile
source /etc/profile
5.修改主机名称
vi /etc/hostname
6.修改域名映射
vi /etc/hosts
添加以下信息：
192.168.12.191 Master1.Hadoop node1
192.168.12.192 Master2.Hadoop node2
192.168.12.193 Slave1.Hadoop node3
192.168.12.194 Slave2.Hadoop node4
192.168.12.195 Slave3.Hadoop node5
重启网络服务生效:
service network restart
7.SSH无密码登陆
7.1 生成公钥和私钥 (每台机器)
输入命令：(一路回车)
ssh-keygen -t rsa
7.2 执行ssh-copy-id（每台机器）
ssh-copy-id -i ~/.ssh/id_rsa.pub root@node1
ssh-copy-id -i ~/.ssh/id_rsa.pub root@node2
ssh-copy-id -i ~/.ssh/id_rsa.pub root@node3
ssh-copy-id -i ~/.ssh/id_rsa.pub root@node4
ssh-copy-id -i ~/.ssh/id_rsa.pub root@node5
- ssh-copy-id将pub值写入远程机器的~/.ssh/authorized_key中
8.NTP时间服务设置
Server端补充添加国内可用NTP服务
server ntp1.aliyun.com iburst minpoll 4 maxpoll 10
restrict ntp1.aliyun.com nomodify notrap nopeer noquery
server ntp1.cloud.aliyuncs.com iburst minpoll 4 maxpoll 10
restrict ntp1.cloud.aliyuncs.com nomodify notrap nopeer noquery
server ntp10.cloud.aliyuncs.com iburst minpoll 4 maxpoll 10
restrict ntp10.cloud.aliyuncs.com nomodify notrap nopeer noquery
server ntp11.cloud.aliyuncs.com iburst minpoll 4 maxpoll 10
restrict ntp11.cloud.aliyuncs.com nomodify notrap nopeer noquery
server ntp12.cloud.aliyuncs.com iburst minpoll 4 maxpoll 10
restrict ntp12.cloud.aliyuncs.com nomodify notrap nopeer noquery
server ntp2.aliyun.com iburst minpoll 4 maxpoll 10
restrict ntp2.aliyun.com nomodify notrap nopeer noquery
server ntp2.cloud.aliyuncs.com iburst minpoll 4 maxpoll 10
restrict ntp2.cloud.aliyuncs.com nomodify notrap nopeer noquery
server ntp3.aliyun.com iburst minpoll 4 maxpoll 10
restrict ntp3.aliyun.com nomodify notrap nopeer noquery
server ntp3.cloud.aliyuncs.com iburst minpoll 4 maxpoll 10
restrict ntp3.cloud.aliyuncs.com nomodify notrap nopeer noquery
server ntp4.aliyun.com iburst minpoll 4 maxpoll 10
restrict ntp4.aliyun.com nomodify notrap nopeer noquery
server ntp4.cloud.aliyuncs.com iburst minpoll 4 maxpoll 10
restrict ntp4.cloud.aliyuncs.com nomodify notrap nopeer noquery
server ntp5.aliyun.com iburst minpoll 4 maxpoll 10
restrict ntp5.aliyun.com nomodify notrap nopeer noquery
server ntp5.cloud.aliyuncs.com iburst minpoll 4 maxpoll 10
restrict ntp5.cloud.aliyuncs.com nomodify notrap nopeer noquery
server ntp6.aliyun.com iburst minpoll 4 maxpoll 10
restrict ntp6.aliyun.com nomodify notrap nopeer noquery
server ntp6.cloud.aliyuncs.com iburst minpoll 4 maxpoll 10
restrict ntp6.cloud.aliyuncs.com nomodify notrap nopeer noquery
server ntp7.cloud.aliyuncs.com iburst minpoll 4 maxpoll 10
restrict ntp7.cloud.aliyuncs.com nomodify notrap nopeer noquery
server ntp8.cloud.aliyuncs.com iburst minpoll 4 maxpoll 10
restrict ntp8.cloud.aliyuncs.com nomodify notrap nopeer noquery
server ntp9.cloud.aliyuncs.com iburst minpoll 4 maxpoll 10
restrict ntp9.cloud.aliyuncs.com nomodify notrap nopeer noquery
