centos7:
查看centos版本 cat /etc/redhat-release
systemctl status firewalld （查看防火墙状态）
systemctl stop firewalld （停止防火墙）
systemctl disable firewalld（禁止开机启动）
安装 wget vim
yum -y install wget
yum -y install vim*
更新yum源为阿里云
1、备份
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
2、下载新的CentOS-Base.repo 到/etc/yum.repos.d/
CentOS 5
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-5.repo
CentOS 6
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
CentOS 7
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo