准备工作
----查看IP
ip addr
vi /etc/sysconfig/network-scripts/ifcfg-xx
service network restart
yum install net-tools
ifconfig
----替换默认源
http://mirrors.163.com/.help/centos.html
SSH
----ssh config为了方便管理多个ssh
cd ~/.ssh/ touch config
congfig 语法：
HostName
Port
User
IdentityFile
----ssh 免密登录
ssh key : ssh-keygen -t rsa
