1.更换yum源备份：mv/etc/yum.repos.d/CentOS-Base.repo/etc/yum.repos.d/CentOS-Base.repo.backup更换：wget-O/etc/yum.repos.d/CentOS-Base.repohttps://mirrors.aliyun.com/repo/Centos-7.repo运行  yummakecache 生成缓存2.CentOS7（使用yum进行安装docker）st