报错信息：

Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock error was
12: Timeout on http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
解决办法：

1.查看网卡

nmcli d

2.cd到 /etc/sysconfig/network-scripts/目录下，查看目录下的文件

cd /etc/sysconfig/network-scripts/

3.编辑文件ifcfg-ens192：

BOOTPROTO=dhcp
  ONBOOT=yes

 

 4.重启网络并验证

systemctl restart network
ping www.baidu.com