centos7 网络配置

报错及原因

已加载插件：fastestmirror, langpacks
Loading mirror speeds from cached hostfile
^CCould not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=updates&infra=stock error was
14: curl#56 - “Callback aborted”

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: updates/7/x86_64

参考方法

这个错误表明在尝试从缓存的hostfile加载镜像速度时，无法解析主机名"mirrorlist.centos.org"。这可能是由于网络问题或DNS解析问题导致的。你可以尝试以下方法解决这个问题：

检查你的网络连接是否正常，确保你可以访问互联网。
尝试使用其他DNS服务器，例如谷歌的公共DNS（8.8.8.8和8.8.4.4）。
如果你在使用代理服务器，请检查代理设置是否正确。
如果问题仍然存在，可能是hostfile缓存的问题。你可以尝试清除缓存并重新加载镜像速度。

建议

如果是新安装的centos系统，可以参考设置静态网络试一试能不能联网；在能联网的情况下，有需要再改为DHCP模式进行排查。（我的情况是刚安装Centos7没有设置DNS，修改为静态网络以及补上DNS即可）