yum安装时提示：This system is not registered with an entitlement server. You can use subscription-manager to register.

提示如下：

[root@ajunyu ~]# yum install yum-utils 
Loaded plugins: fastestmirror, product-id, search-disabled-repos, subscription-manager

This system is not registered with an entitlement server. You can use subscription-manager to register.

Loading mirror speeds from cached hostfile

原因：

https://blog.csdn.net/oraoharu/article/details/106808108

这个Red Hat Subscription Manager订阅管理器，它会让你一直register，禁用就好。
脚本文件: /usr/lib/yum-plugins/subscription-manager.py
配置文件: /etc/yum/pluginconf.d/subscription-manager.conf
调用了脚本 /usr/share/rhsm/repolib.py
去重写或者更新/etc/yum.repos.d/redhat.repo文件。
每次yum调用(不禁掉plugins的情况下)，都会更新此文件。
因此，为了不冲突，可以如下操作:停止掉该插件的使用，在配置文件中把enable=0即可。

[root@ajunyu ~]# vim /etc/yum/pluginconf.d/subscription-manager.conf
[main]
enabled=0

再次安装：

[root@ajunyu ~]# yum install yum-utils
Loaded plugins: fastestmirror, product-id, search-disabled-repos
Loading mirror speeds from cached hostfile
 * base: mirrors.aliyun.com
 * elrepo: mirrors.tuna.tsinghua.edu.cn
 * extras: mirrors.aliyun.com
 * updates: mirrors.aliyun.com
Package yum-utils-1.1.31-54.el7_8.noarch already installed and latest version
Nothing to do