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https://blog.csdn.net/Remberthename/article/details/124070710

centos8在更新yum源时提示

失败 错误:为 repo 'AppStream’下载元数据失败

解决方法：

原因:因原有系统中使用的镜像访问地址在国内访问过慢导致

解决方案：

1、将目录切换到/etc/yum.repos.d目录下

2、修改CentOS-Linux-AppStream.repo、CentOS-Linux-BaseOS.repo、CentOS-Linux-Extras.repo三个文件

3、修改CentOS-Linux-BaseOS.repo

将mirrorlist地址注释掉，取消baseurl的注释，将baseurl的指向地址更改为阿里云镜像的地址

[BaseOS]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/release=$releasever&arch=$basearch&repo=BaseOS&infra=$infra
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

[AppStream] name=CentOS-$releasever - AppStream

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

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

[extras] name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/release=$releasever&arch=$basearch&repo=extras&infra=$infra
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

6、修改完文件后保存，清楚缓存，从新生成元数据

##清楚缓存

yum clean all

##生成元数据

yum makecache

Linux 运维-0006-CentOS 8 升级内核 - 知乎 (zhihu.com)