• centOS7中运行yum安装命令时出现以下错误：

Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock32 error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"
 
One of the configured repositories failed (Unknown),
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.
 
.....................................................................
 4. 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

报错问题是：“安装时网卡没有打开，导致了无法连接网络。”

因此我们需要配置一下网卡，

1. 查看自己本机的网卡，在终端中执行命令：nmcli d
   
2. cd到 /etc/sysconfig/network-scripts/目录下，查看目录下的文件，命令行： cd /etc/sysconfig/network-scripts/ | ls
   
   
3. 打开ifcfg-ens33修改配置,命令行：vim ifcfg-ens33 
   
   
4. 修改配置内容，如下图
   
   
5. 重启一下网络服务，命令行：systemctl restart network
   
   
    
6. 测试网络是否成功，命令行：ping www.baidu.com
   

       到此我们的centOS7已经可以正常访问网络了，尽情的安装吧