错误描述
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
解决步骤
删除redhat原有的yum
rpm -aq|grep yum|xargs rpm -e --nodeps
下载yum安装文件
#到这个网站去下载如下RPM包 http://mirrors.163.com/centos/7/os/x86_64/Packages/
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-3.4.3-163.el7.centos.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-52.el7.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
ll
进行安装yum
rpm -ivh --force --nodeps python-iniparse-0.4-9.el7.noarch.rpm; rpm -ivh --force --nodeps yum-metadata-parser-1.1.4-10.el7.x86_64.rpm rpm -ivh --force --nodeps yum-3.4.3-163.el7.centos.noarch.rpm yum-plugin-fastestmirror-1.1.31-52.el7.noarch.rpm
注意:最后两个包必需同时安装，否则会相互依赖
设置源
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo; cd /etc/yum.repos.d; ll
清除原有缓存
yum clean all
重建缓存，以提高搜索安装软件的速度
yum makecache
如果有提示错误，运行下面的命令：[Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
sed -i ‘s/\$releasever/7/‘ CentOS-Base.repo
备注：把文件里的$releasever替换为7 最后：重新生成缓存，数字不为0，就OK了
yum clean all; yum makecache
更新系统
yum update