使用yum 遇到如下错误. This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register. 因为RedHat yum源是收费的,没有注册的Red Hat是不能使用yum源的. 卸载Red Hat原有的yum,安装centos 7 yum. # 查看本地yum rpm -qa|grep yum # 清除原有RHEL的YUM及相关软件包. r