centos 不能上网,启动eth0 网卡时报错

刚装完CentOs但不能上网，很是纠结。

service network restart出现下面错误：

Error: Connection activation failed: Device not managed by NetworkManager

原因：系统中有两个服务在管理网络，所以需要停掉一个

解决方案：

1、Remove Network Manager from startup Service

#chkconfig NetworkManager off

2. Add Default NetManager

#chkconfig network on

3.Stop NetworkManager first

#service NetworkManager stop

4.and then start Default Manager

#service network restart