今天通过NetworkManager Gui修改了网卡eth0的Gateway,后来reboot了虚拟机，然后奇怪的事情出现了.
1.ifconfig not found eth0

2.systemctl status network,发现如下错误

Bringing up interface eth0:  Error: Connection activation Failed: No suitable device found for this connection.

3.ifup eth0 报一样的错误

google 发现 NetworkManager,network竟然可能会发生冲突. 为避免冲突可以在 /etc/sysconfig/network-scripts/ifcfg-eth* 文件 Disabling Network Manager

TYPE=Ethernet
BOOTPROTO=none
DEVICE=eth0
ONBOOT=yes
#DNS2=114.114.114.114
#DNS1=127.0.0.1
IPADDR=10.0.0.57
PREFIX=24
GATEWAY=10.0.0.1
NM_CONTROLLED=no  # add this line

systemctl start network ok

或者:

1. systemctl stop NetworkManager

2. systemctl disable NetworkManager

3. systemctl start network