centos 8.1 yum 镜像源不能用

Question

Answer 1

应该是镜像源的问题
尝试使用清华的镜像源

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.

[BaseOS]
name=CentOS-$releasever - Base

mirrorlist=http://mirrorlist.centos.org/...$releasever&arch=$basearch&repo=BaseOS&infra=$infra

baseurl=https://mirrors.tuna.tsinghua...$releasever/BaseOS/$basearch/os/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

additional packages that may be useful

[extras]
name=CentOS-$releasever - Extras

mirrorlist=http://mirrorlist.centos.org/...$releasever&arch=$basearch&repo=extras&infra=$infra

baseurl=https://mirrors.tuna.tsinghua...$releasever/extras/$basearch/os/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

additional packages that extend functionality of existing packages

[centosplus]
name=CentOS-$releasever - Plus

mirrorlist=http://mirrorlist.centos.org/...$releasever&arch=$basearch&repo=centosplus&infra=$infra

baseurl=https://mirrors.tuna.tsinghua...$releasever/centosplus/$basearch/os/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

[AppStream]
name=CentOS-$releasever - AppStream

mirrorlist=http://mirrorlist.centos.org/...$releasever&arch=$basearch&repo=AppStream&infra=$infra

baseurl=https://mirrors.tuna.tsinghua...$releasever/AppStream/$basearch/os/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

[PowerTools]
name=CentOS-$releasever - PowerTools

mirrorlist=http://mirrorlist.centos.org/...$releasever&arch=$basearch&repo=PowerTools&infra=$infra

baseurl=https://mirrors.tuna.tsinghua...$releasever/PowerTools/$basearch/os/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

Answer 2

国内的镜像源还是比较多的，你可以考虑换源试一下。
有可能是临时的链路问题，你采用的阿里云镜像一般说来还是比较稳定的。

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