高可用负载均衡部署方案---适用中小应用

1：使用Nginx做两个负载均衡器。其中一个作为备份
2：负载均衡器绑定一个虚拟IP。用户通过虚拟IP访问应用，由负载均衡器进行代理。如果其中一个应用节点失效，Nginx会从负载均衡器中去掉，等到再次可用时，再加入其中。
3：如果负载均衡器1宕机，负载均衡器2接手工作，通过有一个后台作业，不停运行监测，如果载均衡器1不可到达。就给本机添加同一虚拟IP。这样用户访问就被负载均衡器2接手工作，用户使用不需换IP，同样如果负载均衡器2宕机，相同过程被负载均衡器1接手工作
4：如果有域名，可以使用两个VIP，DNS绑定这两个VIP,如果其中一个负载均衡失效，其vip添加到一台负载均衡所在的机子。等失效负载均衡恢复以后，再添加到本机。
5：该方案可以保证任何点，都有一个备份。保持高可用

测试主机：192.168.20.14 和 193.168.20.16
虚拟IP：192.168.20.23

主机环境：
linux 2.6.9-78.EL
apache-tomcat-6.0.26
jdk1.6.0_20
nginx-0.7.67


添加VIP

/sbin/ifconfigeth0:
1

192.168
.
20.23
broadcast
192.168
.
20.255
netmask
255.255
.
255.0
up

/sbin/ifconfig eth0:1 192.168.20.23 broadcast 192.168.20.255 netmask 255.255.255.0 up

切换VIP shell脚本：
主负载均衡运行脚本:nginx_master_ha.sh

#!/bin/sh
LANG=C
date=$(date-d"today"
+
"%Y-%m-%d%H:%M:%S"
)

function_bind_vip(){
/sbin/ifconfigeth0:1

192.168
.
20.23
broadcast
192.168
.
20.255
netmask
255.255
.
255.0
up
}

function_restart_nginx(){
kill-USR1`cat/usr/local/nginx/logs/nginx.pid`
}

function_remove_vip(){
/sbin/ifconfigeth0:1

192.168
.
20.23
broadcast
192.168
.
20.255
netmask
255.255
.
255.0
down
}

bind_vip="N"
;

#主负载均衡。如果发现自己不可用，去掉绑定VIP，这时候备负载均衡会接管
while

true
do
httpcode_local_rip=`/usr/bin/curl-o/dev/null
-s-w%{http_code}http:
//192.168.20.15`

if
[
"x$httpcode_local_rip"
==
'x200'
]
then
if
[
"$bind_vip"
==
"N"
]
then
function_bind_vip
function_restart_nginx
bind_vip="Y"
fi
else
if
[
"$bind_vip"
==
"Y"
]
then
function_remove_vip
bind_vip="N"
fi
fi

sleep5
done

#!/bin/sh
LANG=C
date=$(date -d "today" +"%Y-%m-%d %H:%M:%S")

function_bind_vip() {
	/sbin/ifconfig eth0:1 192.168.20.23 broadcast 192.168.20.255 netmask 255.255.255.0 up
}

function_restart_nginx() {
	kill -USR1 `cat /usr/local/nginx/logs/nginx.pid`
}

function_remove_vip() {
	/sbin/ifconfig eth0:1 192.168.20.23 broadcast 192.168.20.255 netmask 255.255.255.0 down
}

bind_vip="N";

#主负载均衡。如果发现自己不可用，去掉绑定VIP，这时候备负载均衡会接管
while true
do
	httpcode_local_rip=`/usr/bin/curl -o /dev/null -s -w %{http_code} http://192.168.20.15`
	
	if [ "x$httpcode_local_rip" == 'x200' ]
	then
		if [ "$bind_vip" == "N" ]
		then
			function_bind_vip
			function_restart_nginx
			bind_vip="Y"
		fi
	else
		if [ "$bind_vip" == "Y" ]
		then
			function_remove_vip
			bind_vip="N"
		fi
	fi
	
	sleep 5
done

备负载均衡运行脚本:nginx_slave_ha.sh

备负载均衡运行脚本:nginx_slave_ha.sh

#!/bin/sh
LANG=C
date=$(date-d"today"
+
"%Y-%m-%d%H:%M:%S"
)

function_bind_vip(){
/sbin/ifconfigeth0:1

192.168
.
20.23
broadcast
192.168
.
20.255
netmask
255.255
.
255.0
up
}

function_restart_nginx(){
kill-USR1`cat/usr/local/nginx/logs/nginx.pid`
}

function_remove_vip(){
/sbin/ifconfigeth0:1

192.168
.
20.23
broadcast
192.168
.
20.255
netmask
255.255
.
255.0
down
}

bind_vip="N"
;

#备负载均衡。如果发现主负载均衡不可用，由自己接管，当主负载均衡可用时，交由主负载均衡接管
while

true
do
httpcode_remote_rip=`/usr/bin/curl-o/dev/null
-s-w%{http_code}http:
//192.168.20.15`

if
[
"x$httpcode_remote_rip"
!=
'x200'
]
then
if
[
"$bind_vip"
==
"N"
]
then
function_bind_vip
function_restart_nginx
bind_vip="Y"
fi
else
if
[
"$bind_vip"
==
"Y"
]
then
function_remove_vip
bind_vip="N"
fi
fi

sleep5
done

#!/bin/sh
LANG=C
date=$(date -d "today" +"%Y-%m-%d %H:%M:%S")

function_bind_vip() {
	/sbin/ifconfig eth0:1 192.168.20.23 broadcast 192.168.20.255 netmask 255.255.255.0 up
}

function_restart_nginx() {
	kill -USR1 `cat /usr/local/nginx/logs/nginx.pid`
}

function_remove_vip() {
	/sbin/ifconfig eth0:1 192.168.20.23 broadcast 192.168.20.255 netmask 255.255.255.0 down
}

bind_vip="N";

#备负载均衡。如果发现主负载均衡不可用，由自己接管，当主负载均衡可用时，交由主负载均衡接管
while true
do
	httpcode_remote_rip=`/usr/bin/curl -o /dev/null -s -w %{http_code} http://192.168.20.15`
	
	if [ "x$httpcode_remote_rip" != 'x200' ]
	then
		if [ "$bind_vip" == "N"]
		then
			function_bind_vip
			function_restart_nginx
			bind_vip="Y"
		fi
	else
		if [ "$bind_vip" == "Y" ]
		then
			function_remove_vip
			bind_vip="N"
		fi
	fi
	
	sleep 5
done

ngnix.conf配置：

#usernobody;
worker_processes2
;
#error_loglogs/error.log;
#error_loglogs/error.lognotice;
#error_loglogs/error.loginfo;

#pidlogs/nginx.pid;

worker_rlimit_nofile1024
;
events{
useepoll;
worker_connections1024
;
}


http{
includemime.types;
default_typeapplication/octet-stream;

#log_formatmain'$remote_addr-$remote_user[$time_local]"$request"'
#'$status$body_bytes_sent"$http_referer"'
#'"$http_user_agent""$http_x_forwarded_for"'
;

#access_loglogs/access.logmain;

sendfileon;
tcp_nopushon;

#keepalive_timeout0
;
keepalive_timeout65
;

#gzipon;

upstreambackend{
server192.168
.
20.14
:
8080
weight=
10
;
server192.168
.
20.16
:
8080
weight=
10
;
}
server{
listen80
;
server_name192.168
.
20.14
;

#charsetkoi8-r;

#access_loglogs/host.access.logmain;

location/{
roothtml;
indexindex.jspindex.htmlindex.htm;
proxy_set_headerHost$host;
proxy_set_headerX-Real-IP$remote_addr;
proxy_set_headerX-Forwarded-For$proxy_add_x_forwarded_for;
proxy_passhttp://backend;
}


#error_page404
/
404
.html;

#redirectservererrorpagestothestatic
page/50x.html
#
error_page500

502

503

504
/50x.html;
location=/50x.html{
roothtml;
}

}



}

#user  nobody;
worker_processes  2;
#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

#pid        logs/nginx.pid;

worker_rlimit_nofile 1024;
events {
    use epoll;
    worker_connections  1024;
}


http {
    include       mime.types;
    default_type  application/octet-stream;

    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';

    #access_log  logs/access.log  main;

    sendfile        on;
    tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;

    upstream backend { 
	server 192.168.20.14:8080 weight=10; 
	server 192.168.20.16:8080 weight=10; 
    } 
    server {
        listen       80;
        server_name  192.168.20.14;

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        location / {
            root   html;
            index  index.jsp index.html index.htm;
	    proxy_set_header       Host $host;
            proxy_set_header  X-Real-IP  $remote_addr;
            proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_pass  http://backend; 
        }


        #error_page  404              /404.html;

        # redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
        
    }



}