1，近日，拿到同事通过克隆做的一个镜像，上传到云平台，开机后加载网卡，发现eth0获取不到IP，重启network服务
service network restart Shutting downloopback insterface: [ OK ] Bringing uploopback insterface: [ OK ] Bringing upinterface eth0: Device eth0 does notseem to be present,delaying initialization. [FAILED]
2，经过多方查找，是因为克隆时把之前的虚拟机MAC地址信息拷贝到镜像中的网络配置信息中了，存在于eth0网卡中，并且和udev的网卡配置文件eth0字段的MAC关联，从而导致现在用镜像创建云主机开机，udev自动生成一个新的MAC地址后，发现eth0已经存在克隆的MAC信息，所以将新生成的MAC命名为eth1了，由于该eth0的MAC信息为克隆过来的，udev生成的MAC没有同步到eth0网卡的配置里，所以系统认为eth0的MAC信息不正确，因此会启动失败。
解决办法：
（1）将eth0网卡配置信息中MAC改为udev新生成的MAC地址，并且删掉udev网卡信息配置文件中eth0字段，将eth1改成eth0，保存后重启系统。
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.
#net device () (custom name provided by external tool)
SUBSYSTEM==”net”, ACTION==”add”, DRIVERS==”?*”,ATTR{address}==”08:00:27:16:31:11″, ATTR{type}==”1″, KERNEL==”eth*”,NAME=”eth0″
#net device ()
SUBSYSTEM==”net”, ACTION==”add”, DRIVERS==”?*”,ATTR{address}==”08:00:27:32:66:63″, ATTR{type}==”1″, KERNEL==”eth*”,NAME=”eth1″vim /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network-scripts/ifcfg-eth0 HWADDR=08:00:27:16:31:11 #修改为eth1的HWADDR=08:00:27:32:66:63
vim /etc/udev/rules.d/70-persistent-net.rules
SUBSYSTEM==”net”, ACTION==”add”, DRIVERS==”?*”,ATTR{address}==”08:00:27:32:66:63″, ATTR{type}==”1″, KERNEL==”eth*”,NAME=”eth0″
#将eth0那一行删除，然后把eth1改为eth0（2）直接删除/etc/udev/rules.d/70-persistent-net.rules文件（删除该文件不会影响系统崩溃，系统重启后会自动生成），然后删除/etc/sysconfig/network-scripts/ifcfg-eth0中HWADDR和UUID两行，关机重启。
