sudo cp -r /etc/yum.repos.d /etc/yum.repos.d.backup

备份yum源

sudo vim /etc/yum.repos.d/CentOS-Base.repo

编辑yum源仓库

<code>[baseos]

name=CentOS Stream $releasever - BaseOS

baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos-stream/9-stream/BaseOS/$basearch/os/

gpgcheck=1

enabled=1

gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

[appstream]

name=CentOS Stream $releasever - AppStream

baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos-stream/9-stream/AppStream/$basearch/os/

gpgcheck=1

enabled=1

gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

将此代码，插入打开的文件中，将之前文件清空，插入即可。

yum clean all  

yum makecache 

清理文件，建立缓存。