• 2020 年 12 月 8 号，CentOS 官方宣布了停止维护 CentOS Linux 的计划，并推出了 CentOS Stream 项目，CentOS Linux 8 作为 RHEL 8 的复刻版本，生命周期缩短，于 2021 年 12 月 31 日停止更新并停止维护（EOL），更多的信息可以查看 CentOS 官方公告。如果需要更新 CentOS，需要将镜像从 mirror.centos.org 更改为 vault.centos.org

错误代码：

Repository extras is listed more than once in the configuration
CentOS Linux 8 - AppStream                                                              0.0  B/s |   0  B     00:00
Errors during downloading metadata for repository 'appstream':
  - Curl error (6): Couldn't resolve host name for http://mirrorlist.centos.org/?release=8&arch=x86_64&repo=AppStream&infra=stock [Could not resolve host: mirrorlist.centos.org]
Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: Curl error (6): Couldn't resolve host name for http://mirrorlist.centos.org/?release=8&arch=x86_64&repo=AppStream&infra=stock [Could not resolve host: mirrorlist.centos.org]

• 解决方案：

cd /etc/yum.repos.d/  
  
#更新yum源为阿里源  
wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo  
  
sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-\*  
sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-\*  
  
#如果已经安装了wget就不需要这一步  
yum install wget –y  
  
yum clean all  
  
yum makecache  
#验证  
yum install -y vim