重新加载网卡时出现的错误如下：
[root@vdb1 dev]# service network restart
Shutting down interface eth0: Device state: 3 (disconnected)
[ OK ]
Shutting down interface eth1: [ OK ]
Shutting down interface eth2: Device state: 3 (disconnected)
[ OK ]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: Active connection state: activating
Active connection path: /org/freedesktop/NetworkManager/ActiveConnection/23
Error: Timeout 90 sec expired.
[FAILED]
Bringing up interface eth1: Active connection state: activated
Active connection path: /org/freedesktop/NetworkManager/ActiveConnection/25
[ OK ]
Bringing up interface eth2: Active connection state: activated
Active connection path: /org/freedesktop/NetworkManager/ActiveConnection/26
[ OK ]
此时，当前网卡也是可以通信的，但是通过网络管理工具修改IP之后，当前修改操作是不会生效的。那如何消除这个提示呢？
其实，问题的原因是RedHat自己开发的NetworkManager管理工具和/etc/sysconfig/network-scripts/ifcfg-ethx配置不同步造成的。如果要消除这个提示，请关闭NetworkManager服务即可：
[root@vdb1 dev]# chkconfig NetworkManager off --永久关闭服务，需要重启
[root@vdb1 dev]# service NetworkManager stop --立即关闭服务，不需要重启
Stopping NetworkManager daemon: [ OK ]
此时，再重新加载network服务即可：
[root@vdb1 dev]# service network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down interface eth2: [ OK ]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0:
Determining IP information for eth0... failed.
[FAILED]
Bringing up interface eth1: Determining if ip address 192.168.179.181 is already in use for device eth0...
[ OK ]
Bringing up interface eth2: Determining if ip address 172.168.180.191 is already in use for device eth2...
[ OK ]
