查看源：镜像源配置文件在  /etc/yum.repos.d 文件夹下

cd /etc/yum.repos.d

查看源文件：

ls /etc/yum.repos.d/

下载阿里云镜像源：

curl -o /etc/yum.repos.d/CentOS-Base-Aliyun.repo http://mirrors.aliyun.com/repo/Centos-8.repo

打开阿里镜像源文件查看更新镜像源信息，我们可以看到阿里的镜像源中已经配置了[base][extras][centosplus][PowerTools][AppStream]源，系统中原本自带的镜像源就可以屏蔽掉，防止镜像冲突。

# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client.  You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the 
# remarked out baseurl= line instead.
#
#
 
[base]
name=CentOS-$releasever - Base - mirrors.aliyun.com
#failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/BaseOS/$basearch/os/
        http://mirrors.aliyuncs.com/centos/$releasever/BaseOS/$basearch/os/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/BaseOS/$basearch/os/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
 
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - mirrors.aliyun.com
#failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/extras/$basearch/os/
        http://mirrors.aliyuncs.com/centos/$releasever/extras/$basearch/os/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/extras/$basearch/os/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
 
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - mirrors.aliyun.com
#failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/os/
        http://mirrors.aliyuncs.com/centos/$releasever/centosplus/$basearch/os/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/centosplus/$basearch/os/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
 
[PowerTools]
name=CentOS-$releasever - PowerTools - mirrors.aliyun.com
#failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/PowerTools/$basearch/os/
        http://mirrors.aliyuncs.com/centos/$releasever/PowerTools/$basearch/os/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/PowerTools/$basearch/os/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official


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

重命名原来的源进行保存备份
cd /etc/yum.repos.d
sudo mv CentOS-AppStream.repo CentOS-Linux-AppStream.repo_bak
sudo mv CentOS-Base.repo CentOS-Linux-BaseOS.repo_bak
sudo mv CentOS-Extras.repo CentOS-Linux-Extras.repo_bak
sudo mv CentOS-PowerTools.repo  CentOS-Linux-PowerTools.repo_bak
sudo mv microsoft-prod.repo  microsoft-prod.repo_bak
 
yum makecache