故障描述：
# service network restart
Shutting down loopback insterface: [ OK ]
Bringing up loopback insterface: [ OK ]
Bringing up interface eth0: Device eth0 does not seem to be present,delaying initialization. [Failed]
解决方法：
1.修改Centos虚拟机克隆机的HWADDR为ifconfig -a的MAC地址
(或者将/etc/sysconfig/network-scripts/ifcfg-eth0 文件中的HWADDR 行用‘#’注释掉)
形如：HWADDR="00:0C:29:90:A7:23"
2.删除文件后重启
# rm -rf /etc/udev/rules.d/70-persistent-net.rules
# reboot
附/etc/udev/rules.d/70-persistent-net.rules 文件内容如下：
$ cat /etc/udev/rules.d/70-persistent-net.rules
# This file was automatically generated by the /lib/udev/write_net_rules
# program,run by the persistent-net-generator.rules rules file.
#
# You can modify it,as long as you keep each rule on a single
# line,and change only the value of the NAME= key.
# PCI device 0x8086:0x100e (e1000)
SUBSYstem=="net",ACTION=="add",DRIVERS=="?*",ATTR{address}=="08:00:27:d2:a6:db",ATTR{type}=="1",KERNEL=="eth*",NAME="eth0"
