今天小组成员碰到一个情况：
centos6.9只有eth0网卡，但是每次开机启动后都显示的是eth2
经查找，和开机mac自启动网卡有关，涉及文件
/etc/udev/rules.d/70-persistent-net.rules
[imkindu@centos6 scripts]$ 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 0x8086:0x100f (e1000)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:96:be:9c", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"