针对web服务器容灾自动切换方案

思路：
当服务器A 发生故障，服务器B可以迅速接管服务器A的任务，不影响用户的正常访问。
当服务器A 故障恢复，服务器A可以马上接管服务器B的任务，服务器B恢复备机状态。

做法：
两台服务器上配置一个虚拟IP地址，主服务器先绑定虚拟ip地址，当发生故障时，备机自动接管虚拟ip地址，刷新网关路由地址。当主机恢复后，备机释放虚拟ip地址，主机再次主动接管虚拟ip地址，刷新网关路由地址。

结构图：


主服务器：ip 192.168.190.199
备服务器: ip 192.168.190.208

vip：192.168.190.88
gateWay=192.168.190.254
netMask=255.255.255.0
bcast=192.168.190.255

步骤：
1、配置虚拟ip：192.168.190.88 到 www.test.com 绑定虚拟ip
 

/sbin/ifconfig eth0:1 192.168.190.88 broadcast 192.168.190.255
netmask 255.255.255.0  up
/sbin/route add -host 192.168.190.88 dev eth0:1

/sbin/ifconfig eth0:1 192.168.190.88 broadcast 192.168.190.255  
netmask 255.255.255.0  up
/sbin/route add -host 192.168.190.88 dev eth0:1

2、刷新网关路由
 

/sbin/arping -i eth0 -s 192.168.190.88  192.168.190.254 > /dev/null 2>&1

/sbin/arping -i eth0 -s 192.168.190.88  192.168.190.254 > /dev/null 2>&1

3、当发生故障时，主机192.168.190.199 ，释放虚拟ip192.168.190.88，备机192.168.190.208接管 虚拟ip192.168.190.88
 

/sbin/ifconfig eth0:1 192.168.190.88  broadcast  192.168.190.255   netmask 255.255.255.0 down
/sbin/arping -i eth0 -s 192.168.190.88  192.168.190.254 > /dev/null 2>&1

/sbin/ifconfig eth0:1 192.168.190.88  broadcast  192.168.190.255   netmask 255.255.255.0 down        
/sbin/arping -i eth0 -s 192.168.190.88  192.168.190.254 > /dev/null 2>&1

3、这时 www.test.com 解析到了备机服务器192.168.190.208

4、重启备机web服务器

5、若主机192.168.190.199服务恢复正常，备机192.168.190.208释放虚拟IP,主机
绑定虚拟IP 192.168.190.88
备机释放虚拟ip：
 

/sbin/ifconfig eth0:1 192.168.190.88  broadcast  192.168.190.255   netmask 255.255.255.0 down
/sbin/arping -i eth0 -s 192.168.190.88  192.168.190.254 > /dev/null 2>&1

/sbin/ifconfig eth0:1 192.168.190.88  broadcast  192.168.190.255   netmask 255.255.255.0 down        
/sbin/arping -i eth0 -s 192.168.190.88  192.168.190.254 > /dev/null 2>&1

6、重启启动主备机web服务

主机192.168.190.199
autoSwitchMain.sh切换脚本
 

#!/bin/sh
#############################################################
#desc:服务器宕机自动切换服务
#author:gaozhonghui
#mail:toptreegzh@163.com
#date:20121101
#############################################################

vip=192.168.190.88
gateWay=192.168.190.254
netMask=255.255.255.0
bcast=192.168.190.255

function_bind_vip1(){
/sbin/ifconfig eth0:1 ${vip} broadcast ${bcast}  netmask ${netMask} up
/sbin/route add -host ${vip} dev eth0:1
}

function_remove_vip1(){
/sbin/ifconfig eth0:1 ${vip} broadcast ${bcast}  netmask ${netMask down
}

function_vip_arping1(){
/sbin/arping -i eth0 -s ${vip} ${gateWay} > /dev/null 2>&1
}

function_restart_nginx(){
/web/webserver/nginx/sbin/nginx -s reload
}

bind_time_vip="N"

while true
do
    httpCode_rip1=`/usr/bin/curl -o /dev/null -s -w %{http_code} http://192.168.190.199`

    if [ x${httpCode_rip1} == "x200" ];
    then
        if [ ${bind_time_vip} == "N" ];
        then
            function_bind_vip1
            function_vip_arping1
            bind_time_vip="Y"
        fi
        function_vip_arping1
    else
        if [ ${bind_time_vip} == "Y" ]
        then
            function_remove_vip1
            bind_time_vip="N"
        fi
    fi
    sleep 10
done

#!/bin/sh
#############################################################
#desc:服务器宕机自动切换服务
#author:gaozhonghui
#mail:[email protected]
#date:20121101
#############################################################

vip=192.168.190.88
gateWay=192.168.190.254
netMask=255.255.255.0
bcast=192.168.190.255

function_bind_vip1(){
/sbin/ifconfig eth0:1 ${vip} broadcast ${bcast}  netmask ${netMask} up
/sbin/route add -host ${vip} dev eth0:1
}

function_remove_vip1(){
/sbin/ifconfig eth0:1 ${vip} broadcast ${bcast}  netmask ${netMask down
}

function_vip_arping1(){
/sbin/arping -i eth0 -s ${vip} ${gateWay} > /dev/null 2>&1
}

function_restart_nginx(){
/web/webserver/nginx/sbin/nginx -s reload
}

bind_time_vip="N"

while true
do
	httpCode_rip1=`/usr/bin/curl -o /dev/null -s -w %{http_code} http://192.168.190.199`
	
	if [ x${httpCode_rip1} == "x200" ];
	then
		if [ ${bind_time_vip} == "N" ];
		then
			function_bind_vip1
			function_vip_arping1
			bind_time_vip="Y"
		fi
		function_vip_arping1
	else
		if [ ${bind_time_vip} == "Y" ]
		then
			function_remove_vip1
			bind_time_vip="N"
		fi
	fi
	sleep 10
done

然后linux 启动守候进程
/usr/bin/nohup /bin/sh  /home/Gzh/shell/ autoSwitchMain.sh   2>&1 > /dev/null &

备机192.168.190.208:
autoSwitchSlave.sh
 

#!/bin/sh
#############################################################
#desc:服务器宕机自动切换服务
#author:gaozhonghui
#mail:toptreegzh@163.com
#date:20121101
#############################################################

vip=192.168.190.88
gateWay=192.168.190.254
netMask=255.255.255.0
bcast=192.168.190.255

function_bind_vip1(){
/sbin/ifconfig eth0:1 ${vip} broadcast ${bcast}  netmask ${netMask} up
/sbin/route add -host ${vip} dev eth0:1
}

function_remove_vip1(){
/sbin/ifconfig eth0:1 ${vip} broadcast ${bcast}  netmask ${netMask} down
}

function_vip_arping1(){
/sbin/arping -i eth0 -s ${vip} ${gateWay} > /dev/null 2>&1
}

function_restart_nginx(){
/web/webserver/nginx/sbin/nginx -s reload
}

bind_time_vip="N"

while true
do
        httpCode_rip1=`/usr/bin/curl -o /dev/null -s -w %{http_code} http://192.                                                168.190.199`

        if [ x${httpCode_rip1} == "x200" ];
        then
                if [ ${bind_time_vip} == "Y" ];
                then
                        function_remove_vip1
                        bind_time_vip="N"
                fi
                function_vip_arping1
        else
                if [ ${bind_time_vip} == "N" ]
                then
                        function_bind_vip1
                        function_vip_arping1
                        bind_time_vip="Y"
                fi
        fi

        sleep 10
done

#!/bin/sh
#############################################################
#desc:服务器宕机自动切换服务
#author:gaozhonghui
#mail:[email protected]
#date:20121101
#############################################################

vip=192.168.190.88
gateWay=192.168.190.254
netMask=255.255.255.0
bcast=192.168.190.255

function_bind_vip1(){
/sbin/ifconfig eth0:1 ${vip} broadcast ${bcast}  netmask ${netMask} up
/sbin/route add -host ${vip} dev eth0:1
}

function_remove_vip1(){
/sbin/ifconfig eth0:1 ${vip} broadcast ${bcast}  netmask ${netMask} down
}

function_vip_arping1(){
/sbin/arping -i eth0 -s ${vip} ${gateWay} > /dev/null 2>&1
}

function_restart_nginx(){
/web/webserver/nginx/sbin/nginx -s reload
}

bind_time_vip="N"

while true
do
        httpCode_rip1=`/usr/bin/curl -o /dev/null -s -w %{http_code} http://192.                                                168.190.199`

        if [ x${httpCode_rip1} == "x200" ];
        then
                if [ ${bind_time_vip} == "Y" ];
                then
                        function_remove_vip1
                        bind_time_vip="N"
                fi
                function_vip_arping1
        else
                if [ ${bind_time_vip} == "N" ]
                then
                        function_bind_vip1
                        function_vip_arping1
                        bind_time_vip="Y"
                fi
        fi

        sleep 10
done

启动守候进程
/usr/bin/nohup /bin/sh  /home/Gzh/shell/autoSwitchSlave.sh   2>&1 > /dev/null &