1、备份系统旧配置文件
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
2、下载源配置 CentOS6
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.cloud.tencent.com/repo/centos6_base.repo
3、把http替换https
sed -i 's#http#https#g' /etc/yum.repos.d/CentOS-Base.repo
4、清除缓存
yum clean all
yum makecache