CentOS7 更换源

阿里源

mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo_bak
curl http://mirrors.aliyun.com/repo/Centos-7.repo -o /etc/yum.repos.d/CentOS-Base.repo

# 阿里 epel 源
mv /etc/yum.repos.d/epel.repo /etc/yum.repos.d/epel.repo_bak
curl http://mirrors.aliyun.com/repo/epel-7.repo -o /etc/yum.repos.d/epel.repo