Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock error was 14: curl#6 - "Could not resolve host: mirrorlist.centos.org; 未知的错误" One of the configured repositories failed (未知), and yum doesn't have enough cached data to continue. At this point the only safe thing yum can do is fail. There are a few ways to work "fix" this: 1. Contact the upstream for the repository and get them to fix the problem. 2. Reconfigure the baseurl/etc. for the repository, to point to a working upstream. This is most often useful if you are using a newer distribution release than is supported by the repository (and the packages for the previous distribution release still work). 3. Run the command with the repository temporarily disabled yum --disablerepo=<repoid> ... 4. Disable the repository permanently, so yum won't use it by default. Yum will then just ignore the repository until you permanently enable it again or use --enablerepo for temporary usage: yum-config-manager --disable <repoid> or subscription-manager repos --disable=<repoid> 5. Configure the failing repository to be skipped, if it is unavailable. Note that yum will try to contact the repo. when it runs most commands, so will have to try and fail each time (and thus. yum will be be much slower). If it is a very temporary problem though, this is often a nice compromise: yum-config-manager --save --setopt=<repoid>.skip_if_unavailable=true Cannot find a valid baseurl for repo: base/7/x86_64

根据您提供的错误信息，看起来是您的系统无法解析 `mirrorlist.centos.org` 的主机名，导致无法获取CentOS的软件源镜像列表。

这可能是由于DNS配置不正确或网络连接问题导致的。请尝试以下步骤来解决该问题：

1. 确保您的网络连接正常。尝试通过访问其他网站来确认网络是否正常工作。

2. 检查您的DNS配置。可以通过编辑 `/etc/resolv.conf` 文件来确认 DNS 设置是否正确。确保其中的 `nameserver` 行指定了可用的DNS服务器地址。例如：

   nameserver 8.8.8.8
   nameserver 8.8.4.4

这里使用的是谷歌的公共DNS服务器地址，您也可以根据需要使用其他可靠的DNS服务器地址。

3. 如果您使用的是CentOS 7，还可以尝试更新系统中的`ca-certificates`软件包。运行以下命令来更新软件包并重新生成CA证书：

   sudo yum update ca-certificates
   sudo update-ca-trust force-enable
   sudo update-ca-trust extract

4. 如果问题仍然存在，您可以尝试使用其他可用的软件源镜像。编辑 `/etc/yum.repos.d/CentOS-Base.repo` 文件，将 `mirrorlist` 行注释掉，并取消注释 `baseurl` 行，并将 `baseurl` 行的值更改为其他可用的镜像源地址。例如，您可以使用 `http://vault.centos.org` 作为基础URL：

   baseurl=http://vault.centos.org/7.0.1406/os/x86_64/

保存文件并尝试再次运行 `yum` 命令。

如果以上步骤都没有解决问题，请确保您的网络环境没有其他限制或防火墙规则阻止访问软件源镜像。如果问题仍然存在，建议联系您的系统管理员或CentOS支持获取进一步的帮助。