centos7切阿里云源

#  验证网络
ping mirrors.aliyun.com

# 备份CentOS 7系统自带yum源配置文件/etc/yum.repos.d/CentOS-Base.repo命令：
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

# 安装wget
yum install -y wget

# 下载CentOS 7的repo文件
wget -O /etc/yum.repos.d/CentOS-Base.repo <http://mirrors.aliyun.com/repo/Centos-7.repo>

# 清理
yum clean all

# 缓存
yum makecache

# 更新
yum update