Today, the newly installed Centos 7, the results just machines appeared "can not find a valid basecrl for repo: base / 7 / x86_64" error, after debugging, the card is not activated, the following operating, start it like a card
Reference connecting portion:
https://www.glbwl.com/centos-7-repo-base.html
https://blog.csdn.net/u013091013/article/details/70919291
cd /etc/sysconfig/network-scripts
ls
vi ifcfg-ens33
The [ ONBOOT = no ] into [ ONBOOT = yes ]
service network restart