配置网络yum源1.备份当前的YUM仓库配置文件，以防需要恢复：cp/etc/yum.repos.d/CentOS-Base.repo/etc/yum.repos.d/CentOS-Base.repo.backup2.配置网易yum源：wgethttp://mirrors.163.com/.help/CentOS7-Base-163.repo-O/etc/yum.repos.d/CentOS-Base.repo3.清除YUM缓存