虚拟机安装yum插件出错。ping百度，ping不通

具体报错是
Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist

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

在网上查，说是可以在图形化界面更改有线网络设置，但是我这边是没有图形化介面的。

ping百度，ping不通。

这句话就能看出来你的网络并没有连接，你如果有网线的话，直接插上试试，或者试试USB共享网络；虚拟机的话可以更改虚拟机网络设置。

你的网络有问题；

你需要设置动态ip或者静态IP；

同时，你物理机和虚拟机也需要设置网络，

这样才可以使用网络哦；

ip a命令查看网络是否有IP地址，如果没有就代表你的网络配置有问题，还可以重启一下网卡。

解决了，我把网关配错了。