mkdir -p /etc/yum.repos.d/bak
mv /etc/yum.repos.d/* /etc/yum.repos.d/bak
2、添加新的yum源
vim /etc/yum.repos.d/CentOS-Base.repo
添加如下内容：
[base]
name=CentOS-8.5.2111 - Base - mirrors.aliyun.com
baseurl=http://mirrors.aliyun.com/centos-vault/8.5.2111/BaseOS/$basearch/os/
http://mirrors.aliyuncs.com/centos-vault/8.5.2111/BaseOS/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos-vault/8.5.2111/BaseOS/$basearch/os/
gpgcheck=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
#additional packages that may be useful
[extras]
name=CentOS-8.5.2111 - Extras - mirrors.aliyun.com
baseurl=http://mirrors.aliyun.com/centos-vault/8.5.2111/extras/$basearch/os/
http://mirrors.aliyuncs.com/centos-vault/8.5.2111/extras/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos-vault/8.5.2111/extras/$basearch/os/
gpgcheck=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-8.5.2111 - Plus - mirrors.aliyun.com
baseurl=http://mirrors.aliyun.com/centos-vault/8.5.2111/centosplus/$basearch/os/
http://mirrors.aliyuncs.com/centos-vault/8.5.2111/centosplus/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos-vault/8.5.2111/centosplus/$basearch/os/
gpgcheck=0
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
[PowerTools]
name=CentOS-8.5.2111 - PowerTools - mirrors.aliyun.com
baseurl=http://mirrors.aliyun.com/centos-vault/8.5.2111/PowerTools/$basearch/os/
http://mirrors.aliyuncs.com/centos-vault/8.5.2111/PowerTools/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos-vault/8.5.2111/PowerTools/$basearch/os/
gpgcheck=0
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
[AppStream]
name=CentOS-8.5.2111 - AppStream - mirrors.aliyun.com
baseurl=http://mirrors.aliyun.com/centos-vault/8.5.2111/AppStream/$basearch/os/
http://mirrors.aliyuncs.com/centos-vault/8.5.2111/AppStream/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos-vault/8.5.2111/AppStream/$basearch/os/
gpgcheck=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
3、添加appstream
vim /etc/yum.repos.d/CentOS-AppStream.repo
添加如下内容
[AppStream]
name=CentOS-8.5.2111 - AppStream - mirrors.aliyun.com
baseurl=http://mirrors.aliyun.com/centos-vault/8.5.2111/AppStream/$basearch/os/
http://mirrors.aliyuncs.com/centos-vault/8.5<