How to fix CentOS 7 network card down after power-on or reboot
Check /etc/sysconfig/network
# cat /etc/sysconfig/network | grep -i networking
NETWORKING=no
Make sure the value of NETWORKING is set to ‘yes’
Check /etc/sysconfig/network-scripts/ifcfg-eth0
# cat /etc/sysconfig/network-scripts/ifcfg-eth0 | grep -i onboot
ONBOOT=no
Make sure the value of ONBOOT is set to ‘yes’