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
