在我使用虚拟机，系统在尝试访问CentOS的镜像列表时遇到了网络问题，具体表现为无法解析mirrorlist.centos.org
于是手动配置yum仓库
备份现有的 repo 文件
sudo mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup创建新的 repo 文件： 使用文本编辑器（如 vi 或 nano）创建一个新的 repo 文件 /etc/yum.repos.d/CentOS-Base.repo 并添加以下内容。这里我们使用阿里云的镜像源作为示例
sudo vi /etc/yum.repos.d/CentOS-Base.repo按i进入插入模式
[base]
name=CentOS-$releasever - Base
baseurl=https://mirrors.aliyun.com/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
[updates]
name=CentOS-$releasever - Updates
baseurl=https://mirrors.aliyun.com/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
[extras]
name=CentOS-$releasever - Extras
baseurl=https://mirrors.aliyun.com/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
[centosplus]
name=CentOS-$releasever - Plus
baseurl=https://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7先点esc，然后打出:,然后输入wq，回车
清除 Yum 缓存并重新生成缓存
sudo yum clean all
sudo yum makecache
