#删除官方源
rm -rf /etc/yum.repos.d*

#添加阿里云的镜像源和EPEL源
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo && yum -y install epel-release

#重新生成缓存
yum makecache & yum makecache fast

#更新软件包
yum update -y