【转载】完美解决CentOS8 yum安装AppStream报错，更新yum后无法makecache的问题

问题

CentOS 8 yum安装软件时，提示无法从AppStream下载

[root@C8-3 ~]# yum -y install httpd mariadb-server mariadb php php-mysql
Repository AppStream is listed more than once in the configuration
Repository extras is listed more than once in the configuration
Repository PowerTools is listed more than once in the configuration
Repository centosplus is listed more than once in the configuration
Repository fasttrack is listed more than once in the configuration
CentOS-8 - AppStream                           0.0  B/s |   0  B     00:08    
Failed to download metadata for repo 'AppStream'
Error: Failed to download metadata for repo 'AppStream'

更换国内yum源

阿里yum源： https://developer.aliyun.com/mirror/centos
腾云yum源： https://mirrors.tencent.com/help/centos.html

1 2	`# mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup.3` `# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.cloud.tencent.com/repo/centos8_base.repo`

清理之前的yum缓存

1	`# yum clean all`

建立新的缓存

1	`# yum makecache`

解决makecahe报错

centos8会出现以下报错

CentOS-8 - AppStream                           0.0  B/s |   0  B     00:04    
Failed to download metadata for repo 'AppStream'
Error: Failed to download metadata for repo 'AppStream'

解决办法

将CentOS-AppStream.repo文件中的链接更新

1	`# vim /etc/yum.repos.d/CentOS-AppStream.repo`

注释掉原有内容，并插入新内容

#这一段注释掉<br>#[AppStream]
#name=CentOS-$releasever - AppStream
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=AppStream&infra=$infra
#baseurl=http://mirror.centos.org/$contentdir/$releasever/AppStream/$basearch/os/
#mirrorlist=http://mirror.centos.org/$contentdir/$releasever/AppStream/$basearch/os/
#gpgcheck=1
#enabled=1
#pgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial
<br>#改为下面这段
[AppStream]
name=Qcloud centos AppStream - $basearch
baseurl=http://mirrors.cloud.tencent.com/centos/$releasever/AppStream/$basearch/os/
enabled=0
gpgcheck=1
gpgkey=http://mirrors.cloud.tencent.com/centos/RPM-GPG-KEY-CentOS-Official