原文出处 https://www.cnblogs.com/LandWind/p/centos-stream-9-repo-set-aliyun.html

把/etc/yum.repo.d目录下的*.repo备份，然后新建一个centos.repo，把下面的内容粘贴到里面：
[base]
name=CentOS-$releasever – Base – mirrors.aliyun.com
#failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos-stream/$stream/BaseOS/$basearch/os/
http://mirrors.aliyuncs.com/centos-stream/$stream/BaseOS/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos-stream/$stream/BaseOS/$basearch/os/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos-stream/RPM-GPG-KEY-CentOS-Official

#additional packages that may be useful
#[extras]
#name=CentOS-$releasever – Extras – mirrors.aliyun.com
#failovermethod=priority
#baseurl=https://mirrors.aliyun.com/centos-stream/$stream/extras/$basearch/os/
# http://mirrors.aliyuncs.com/centos-stream/$stream/extras/$basearch/os/
# http://mirrors.cloud.aliyuncs.com/centos-stream/$stream/extras/$basearch/os/
#gpgcheck=1
#gpgkey=https://mirrors.aliyun.com/centos-stream/RPM-GPG-KEY-CentOS-Official

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever – Plus – mirrors.aliyun.com
#failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos-stream/$stream/centosplus/$basearch/os/
http://mirrors.aliyuncs.com/centos-stream/$stream/centosplus/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos-stream/$stream/centosplus/$basearch/os/
gpgcheck=1
enabled=0
gpgkey=https://mirrors.aliyun.com/centos-stream/RPM-GPG-KEY-CentOS-Official

[PowerTools]
name=CentOS-$releasever – PowerTools – mirrors.aliyun.com
#failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos-stream/$stream/PowerTools/$basearch/os/
http://mirrors.aliyuncs.com/centos-stream/$stream/PowerTools/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos-stream/$stream/PowerTools/$basearch/os/
gpgcheck=1
enabled=0
gpgkey=https://mirrors.aliyun.com/centos-stream/RPM-GPG-KEY-CentOS-Official


[AppStream]
name=CentOS-$releasever – AppStream – mirrors.aliyun.com
#failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos-stream/$stream/AppStream/$basearch/os/
http://mirrors.aliyuncs.com/centos-stream/$stream/AppStream/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos-stream/$stream/AppStream/$basearch/os/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos-stream/RPM-GPG-KEY-CentOS-Official
保存退出
yum clean all
yum makecache
yum update