報錯如下：

Updating Subscription Management repositories.

Unable to read consumer identity

This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.

Error: There are no enabled repos.

翻譯一下就是：無法讀取用戶標識
此系統(tǒng)未注冊到“紅帽訂閱管理”。您可以使用訂閱管理器進行注冊。
錯誤:沒有啟用的回購。

解決方案：干掉yum，重新裝個centos的yum

# 1. 刪除系統(tǒng)自帶yum包
[root@localhost ~]# rpm -qa|grep yum
yum-4.0.9.2-5.el8.noarch
# 2. 不檢查依賴直接刪除所有yum包
[root@localhost ~]# rpm -qa|grep yum|xargs rpm -e --nodeps
#  3. 檢查是否刪除成功
[root@localhost ~]# rpm -qa|grep yum

下一步，安裝yum，使用阿里云鏡像，找一下最新版的yum包，和 python3-urllib包

 https://mirrors.aliyun.com/centos/8/BaseOS/x86_64/os/Packages/  

wget  https://mirrors.aliyun.com/centos/8/BaseOS/x86_64/os/Packages/yum-4.7.0-4.el8.noarch.rpm
wget  https://mirrors.aliyun.com/centos/8/BaseOS/x86_64/os/Packages/yum-utils-4.0.21-3.el8.noarch.rpm
wget  https://mirrors.aliyun.com/centos/8/BaseOS/x86_64/os/Packages/python3-urllib3-1.24.2-5.el8.noarch.rpm
wget  https://mirrors.aliyun.com/centos/8/BaseOS/x86_64/os/Packages/dnf-4.7.0-4.el8.noarch.rpm
wget  https://mirrors.aliyun.com/centos/8/BaseOS/x86_64/os/Packages/python3-dnf-4.7.0-4.el8.noarch.rpm
wget  https://mirrors.aliyun.com/centos/8/BaseOS/x86_64/os/Packages/python3-dnf-plugins-core-4.0.21-3.el8.noarch.rpm

安裝

[root@localhost ~]# rpm -ivh --force --nodeps python3-dnf-4.7.0-4.el8.noarch.rpm
warning: python3-dnf-4.7.0-4.el8.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID 8483c65d: NOKEY
Verifying...                          ################################# [100%]
Preparing...                          ################################# [100%]
Updating / installing...
   1:python3-dnf-4.7.0-4.el8          ################################# [100%]
[root@localhost ~]# rpm -ivh --force --nodeps python3-dnf-plugins-core-4.0.21-3.el8.noarch.rpm
warning: python3-dnf-plugins-core-4.0.21-3.el8.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID 8483c65d: NOKEY
Verifying...                          ################################# [100%]
Preparing...                          ################################# [100%]
Updating / installing...
   1:python3-dnf-plugins-core-4.0.21-3################################# [100%]
[root@localhost ~]# rpm -ivh --force --nodeps dnf-4.7.0-4.el8.noarch.rpm
warning: dnf-4.7.0-4.el8.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID 8483c65d: NOKEY
Verifying...                          ################################# [100%]
Preparing...                          ################################# [100%]
Updating / installing...
   1:dnf-4.7.0-4.el8                  ################################# [100%]
[root@localhost ~]# rpm -ivh --force --nodeps yum-4.7.0-4.el8.noarch.rpm
warning: yum-4.7.0-4.el8.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID 8483c65d: NOKEY
Verifying...                          ################################# [100%]
Preparing...                          ################################# [100%]
Updating / installing...
   1:yum-4.7.0-4.el8                  ################################# [100%]
[root@localhost ~]# rpm -ivh --force --nodeps yum-utils-4.0.21-3.el8.noarch.rpm
warning: yum-utils-4.0.21-3.el8.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID 8483c65d: NOKEY
Verifying...                          ################################# [100%]
Preparing...                          ################################# [100%]
Updating / installing...
   1:yum-utils-4.0.21-3.el8           ################################# [100%]
[root@localhost ~]# rpm -ivh --force --nodeps python3-urllib3-1.24.2-5.el8.noarch.rpm
warning: python3-urllib3-1.24.2-5.el8.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID 8483c65d: NOKEY
Verifying...                          ################################# [100%]
Preparing...                          ################################# [100%]
Updating / installing...
   1:python3-urllib3-1.24.2-5.el8     ################################# [100%]
[root@localhost ~]#