[root@837 ~]# sudo mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
[root@837 ~]# sudo curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 2523 100 2523 0 0 42607 0 --:--:-- --:--:-- --:--:-- 42762
[root@837 ~]# sudo yum clean all
Loaded plugins: fastestmirror
Cleaning repos: base extras updates
[root@837 ~]# sudo yum makecache