订阅插件提示：This system is not registered with an entitlement server. You can use subscription-manager to

【问题】
订阅插件提示：This system is not registered with an entitlement server. You can use subscription-manager to…

[root@Oradb1 tmp]# yum install gcc-c++
Loaded plugins: langpacks, product-id, search-disabled-repos, subscription-manager
This system is not registered with an entitlement server. You can use subscription-manager to register.
Package gcc-c++-4.8.5-16.el7.x86_64 already installed and latest version
Nothing to do

【解决办法】
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@Oradb1 pluginconf.d]# vim /etc/yum/pluginconf.d/subscription-manager.conf
[main]
enabled=0           #将它禁用掉

【结果】

[root@Oradb1 pluginconf.d]# yum install gcc-c++
Loaded plugins: langpacks, product-id, search-disabled-repos
Package gcc-c++-4.8.5-16.el7.x86_64 already installed and latest version
Nothing to do