自己写 shell 来完成 HA（初试）

初步测试成功，可以实现热切换，不必等待漫长的 arp time out，但需要一块心跳网卡

#! /bin/bash
LAN_IP=192.168.0.254
LAN_MASK=255.255.255.0
WAN_IP=172.17.39.250
WAN_MASK=255.255.255.0
WAN_GATEWAY=172.17.39.254
OTHER_IP="10.1.1.1"
WAN_ETH=eth0
LAN_ETH=eth1
LAST_FLAG=M
SLEEP=10

WAN_MAC=`ip addr list dev $WAN_ETH|grep ether|awk '{print $2}'`
LAN_MAC=`ip addr list dev $LAN_ETH|grep ether|awk '{print $2}'`

while : ; do
        LOCAL_IP=`ifconfig eth2|grep inet|awk '{print $2}'|awk -F: '{print $2}'`
        if [ "$LOCAL_IP" != "$OTHER_IP" ]; then
                if ping -c1 -w1 $OTHER_IP &>/dev/null; then
                        if [ "$LAST_FLAG" = "S" ]; then
                                ifconfig $WAN_ETH down
                                ifconfig $LAN_ETH down
                                ifconfig $WAN_ETH hw ether $WAN_MAC
                                ifconfig $LAN_ETH hw ether $LAN_MAC
                                ifconfig eth2 10.1.1.2 netmask 255.255.255.252
                                LAST_FLAG=M
                        fi
                else
                        if [ "$LAST_FLAG" = "M" ]; then
                                ifconfig $WAN_ETH down
                                ifconfig $LAN_ETH down
                                ifconfig $WAN_ETH hw ether 00:01:19:80:03:09
                                ifconfig $LAN_ETH hw ether 00:02:19:80:03:09
                                ifconfig $WAN_ETH $WAN_IP netmask $WAN_MASK
                                ifconfig $LAN_ETH $LAN_IP netmask $LAN_MASK
                                ip route replace via $WAN_GATEWAY
                                ifconfig eth2 10.1.1.1 netmask 255.255.255.252
                                LAST_FLAG=S
                        fi
                fi
        fi
        sleep $SLEEP
done