安装CDH
配置五个节点，有几个节点是虚拟机
为了方便在Windows中用webUI，编辑C:\Windows\System32\Drivers\etc\hosts，加入如下地址和主机名
下面是要在各节点上执行的：
1.修改主机名
centos7中修改hostname里的名字后重启主机名会恢复成以前的样子
要用hostnamectl set-hostname 主机名来修改
参考：https://www.server-world.info/en/note?os=CentOS_7&p=hostname
https://www.jianshu.com/p/39d7000dfa47
2.关闭防火墙及SE Linux
$>systemctl stop firewalld.service
$>systemctl disable firewalld.service
$>sudo vim /etc/selinux/config
selinux=enforcing改成selinux=disabled
3.修改hosts
$>sudo vim /etc/hosts
去掉命令行提示声
设置虚拟机桥接、配置静态地址
随后配置了ssh和ntp
ssh：
1.删除所有主机上的/home/centos/.ssh/*
2.在nn1主机上生成密钥对
$>ssh-keygen -t rsa -P '' -f ~/.ssh/id_rsa
3.将nn1的公钥文件id_rsa.pub远程复制到202 ~ 204主机上。
并放置/home/centos/.ssh/authorized_keys
$>scp id_rsa.pub centos@nn1:/home/centos/.ssh/authorized_keys
$>scp id_rsa.pub centos@nn2:/home/centos/.ssh/authorized_keys
$>scp id_rsa.pub centos@dn1:/home/centos/.ssh/authorized_keys ....... 都发过去
scp id_rsa.pub 用户名@主机名:/home/centos/.ssh/authorized_keys
ntp：
各个节点装yum -y install ntp
设定时区timedatectl set-timezone Asia/Shanghai
编辑vi /etc/ntp.conf
由于是局域网内节点较少就不按照标准的服务器去同步时间了，以nn1即192.168.1.21的时间为准
server里加这个
server 192.168.1.21 prefer
server 192.168.1.22
server 127.127.1.0
fudge 127.127.1.0 stratum 8
restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery
restrict 192.168.1.21
restrict 192.168.1.22
restrict 192.168.1.23
restrict 192.168.1.24
restrict 192.168.1.25
client里加这个
server 192.168.1.21 prefer
server 192.168.1.22
server 127.127.1.0
fudge 127.127.1.0 stratum 8
restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery
restrict 192.168.1.21
restrict 192.168.1.22
每个节点运行这个
# systemctl start ntpd
# systemctl enable ntpd
https://blog.csdn.net/loopeng1/article/details/79051884
设置vm共享文件夹
https://blog.csdn.net/Ahuuua/article/details/90053218
不行了，后面的安装就跟着这个走了
https://blog.csdn.net/dongyunlon/article/details/79755791
https://www.cnblogs.com/skyrim/p/7455484.html#%E5%AE%89%E8%A3%85%E4%B8%AD%E5%87%BA%E7%8E%B0%E7%9A%84%E9%97%AE%E9%A2%98