Centos 8 在使用yum命令时提示错误

“为 repo 'appstream' 下载元数据失败 : Cannot prepare internal mirrorlist: No URLs in mirrorlist”

如下图

解决方案如下：

进入/etc/yum.repos.d/目录下，修改CentOS-Linux-AppStream.repo、CentOS-Linux-BaseOS.repo、CentOS-Linux-Extras.repo

注释mirrorlist，取消注释并编辑baseurl文件 

编辑CentOS-Linux-AppStream.repo 文件

[appstream]
name=CentOS Linux $releasever - AppStream
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=AppStream&infra=$infra
#baseurl=http://mirror.centos.org/$contentdir/$releasever/AppStream/$basearch/os/
baseurl=http://mirrors.aliyun.com/centos/8-stream/AppStream/x86_64/os/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

 编辑CentOS-Linux-BaseOS.repo 文件

[baseos]
name=CentOS Linux $releasever - BaseOS
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=BaseOS&infra=$infra
#baseurl=http://mirror.centos.org/$contentdir/$releasever/BaseOS/$basearch/os/
baseurl=http://mirrors.aliyun.com/centos/8-stream/BaseOS/x86_64/os/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

编辑CentOS-Linux-Extras.repo 文件

[extras]
name=CentOS Linux $releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras&infra=$infra
#baseurl=http://mirror.centos.org/$contentdir/$releasever/extras/$basearch/os/
baseurl=http://mirrors.aliyun.com/centos/8-stream/extras/x86_64/os/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

修改完文件，清除缓存，重新生成元数据文件

#清除缓存文件
yum clean all

#生成元数据缓存
yum makecache

 创建元数据缓存后，重新使用yum命令安装