实现环境: centos7   Linux devstack01 3.10.0-693.el7.x86_64

cp ifcfg-br0 ifcfg-br2

vim ifcfg-br2
将其中的IP和网关改为eth2的
DEVICE=br2
TYPE=Bridge
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
DEFROUTE=yes
NAME=br2
ONBOOT=yes
IPADDR=192.168.253.128
PREFIX=24
GATEWAY=192.168.253.1
DNS1=223.5.5.5

vim ifcfg-eth2
TYPE="Ethernet"
BOOTPROTO="none"
DEVICE="eth2"
ONBOOT="yes"
BRIDGE=br2

systemctl restart network.service