由于 CentOS 8 官方已终止支持，需要手动调整仓库配置才能继续操作。以下是完整修复方案：

临时修复（使用 CentOS Vault 存档）

清理旧仓库配置

sudo rm -rf /etc/yum.repos.d/CentOS-*

手动创建新仓库文件

sudo tee /etc/yum.repos.d/CentOS-vault.repo <<'EOF'
[baseos]
name=CentOS Linux 8 - BaseOS
baseurl=http://vault.centos.org/8.5.2111/BaseOS/$basearch/os/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

[appstream]
name=CentOS Linux 8 - AppStream
baseurl=http://vault.centos.org/8.5.2111/AppStream/$basearch/os/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

[extras]
name=CentOS Linux 8 - Extras
baseurl=http://vault.centos.org/8.5.2111/extras/$basearch/os/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial
EOF

安装 centos-release-stream

sudo yum clean all
sudo yum install centos-release-stream -y