1.輸入該命令按回車鍵：`dnf -y install epel-release`

2.輸入該命令按回車鍵：`dnf -y update`

3.輸入該命令按回車鍵：`dnf -y install rpmconf yum-utils`

4.輸入該命令按回車鍵：`rpmconf -a`，若出現(xiàn)提示輸入Y按回車鍵

5.輸入該命令按回車鍵：`dnf -y remove rpmconf yum-utils epel-release`

6.輸入該命令按回車鍵： rpm -e --nodeps `rpm -qa|grep centos`

7.輸入該命令按回車鍵： rpm -ivh --nodeps --force https://mirrors.aliyun.com/centos-stream/9-stream/BaseOS/x86_64/os/Packages/centos-stream-release-9.0-12.el9.noarch.rpm，  

8.輸入該命令按回車鍵： rpm -ivh --nodeps --force https://mirrors.aliyun.com/centos-stream/9-stream/BaseOS/x86_64/os/Packages/centos-gpg-keys-9.0-12.el9.noarch.rpm  

9.輸入該命令按回車鍵： rpm -ivh --nodeps --force https://mirrors.aliyun.com/centos-stream/9-stream/BaseOS/x86_64/os/Packages/centos-stream-repos-9.0-12.el9.noarch.rpm，  

10.輸入該命令按回車鍵：`dnf clean all`

11.輸入該命令按回車鍵： dnf -y --releasever=9 --allowerasing --setopt=deltarpm=false distro-sync

12.輸入該命令按回車鍵：`rpm --rebuilddb`

13.輸入該命令按回車鍵： rpm -e --nodeps `rpm -qa|grep -i kernel`

14.輸入該命令按回車鍵：`dnf -y install kernel`

15.輸入該命令按回車鍵：`dnf -y install kernel-core`

16.輸入該命令按回車鍵：`dnf -y install shim`

17.輸入該命令按回車鍵：`dnf group install minimal-environment -y`

18.輸入該命令按回車鍵：`dnf -y install epel-release`

19.輸入該命令按回車鍵：`dnf -y install rpmconf yum-utils` 

20.輸入該命令按回車鍵：`dnf -y update`

21.輸入該命令按回車鍵：`rpmconf -a`，若出現(xiàn)提示輸入Y按回車鍵

22.輸入該命令按回車鍵：`grub2-mkconfig -o /boot/grub2/grub.cfg`

23.輸入該命令按回車鍵：`grub2-install /dev/sda`

24.輸入該命令按回車鍵：`echo "PermitRootLogin yes" >> /etc/ssh/sshd_config`

25.輸入該命令按回車鍵重啟后再操作連接：`reboot`

26.輸入該命令按回車鍵查看版本：`cat /etc/redhat-release`