haproxy+keepalived实现高可用负载均衡

工作原理：
Keepalived检测HAproxy主备服务器，利用Keepalived的VIP漂移技术，若HAprox主备都工作正常，则VIP与优先级别高的服务器（主服务器）绑定，当主服务器当掉时，则与备服务器绑定，而VIP则是暴露给外部访问的ip；HAproxy利用Keepalived生产的VIP对web服务器集群进行读负载，当某台we服务器当掉，则将其移除，恢复后再将其加入集群。

说明：
haproxy+keepalived 主：172.16.0.111
haproxy+keepalived 备：172.16.0.112
web-1：172.16.0.113
web-2：172.16.0.114
VIP:172.16.0.110
haproxy-1.5.19.tar.gz
keepalived-1.2.23
1、web服务器上

[root@web-1 ~]# vim  /var/www/html/index.php
<h1>web-1 172.16.0.113</h1>
<?php phpinfo(); ?>

2、安装haproxy，主备配置一样

[root@haproxy-master ~]# tar -zxvf haproxy-1.5.19.tar.gz 
[root@haproxy-master ~]# cd haproxy-1.5.19
[root@haproxy-master haproxy-1.5.19]# make TARGET=linux2628 ARCH=x86_64 PREFIX=/usr/local/haproxy
[root@haproxy-master haproxy-1.5.19]# make install PREFIX=/usr/local/haproxy

编辑配置文件（自己创建，examples目录下有模板）

[root@haproxy-master haproxy-1.5.19]# mkdir -p /usr/local/haproxy/etc
[root@haproxy-master haproxy-1.5.19]# cp ~/haproxy-1.5.19/examples/haproxy.cfg /usr/local/haproxy/etc/
[root@haproxy-master haproxy-1.5.19]# vim /usr/local/haproxy/etc/haproxy.cfg
# this config needs haproxy-1.1.28 or haproxy-1.2.1  
global  
    log 127.0.0.1   local0  
    log 127.0.0.1   local1 notice  
    #log loghost    local0 info    
    maxconn 4096                    #最大连接数    
    chroot /usr/local/haproxy  
    uid 99                       #所属运行的用户UID    
    gid 99                       #所属运行的用户组    
    daemon                       #以后台形式运行HAProxy    
    #debug    
    #quieti    
    nbproc    1    #启动1个实例,可以启多个来提高效率        
    pidfile /var/run/haproxy.pid  

defaults  
    log global  
    mode    http  
    option httpclose               #每次请求完毕后主动关闭http通道    
    option  redispatch               #当serverId对应的服务器挂掉后,强制定向到其他健康的服务器    
    option forwardfor  
    option abortonclose             #当服务器负载很高的时候,自动结束掉当前队列处理比较久的链接    
    option dontlognull                #保证HAProxy不记录上级负载均衡发送过来的用于检测状态没有数据的心跳包    
    retries 2                    #重试次数    
    maxconn 2000                   #最大连接数    
    balance source                #如果想让HAProxy按照客户端的IP地址进行负载均衡策略,即同一IP地址的所有请求都发送到同一服务器时需要配置此选项    
    timeout connect 5000  
    timeout client 50000  
    timeout server 50000  

listen admin_stats  
    bind *:8888              #监听端口，后面打开网页时要用到，不要和已打开的端口冲突  
    mode http               #http的7层模式    
    option httplog            #采用http日志格式    
    log 127.0.0.1 local0 err  
    maxconn 10  
    stats refresh 30s           #统计页面自动刷新时间    
    stats uri /stats          #统计页面url    
    stats auth admin:admin      #统计页面用户名和密码设置    
    stats hide-version         #隐藏统计页面上HAProxy的版本信息  

#关键设置，添加负载均衡服务器只需设置这里  
 listen  web_cluster 0.0.0.0:8090  
    mode http   
    balance roundrobin   
    server web1 172.16.0.113:80 cookie app1inst1 check inter 2000 rise 2 fall 5   
    server web2 172.16.0.114:80 cookie app1inst2 check inter 2000 rise 2 fall 5

启动

[root@localhost sbin]# /usr/local/haproxy/sbin/haproxy  -f  /usr/local/haproxy/etc/haproxy.cfg 

停止

[root@localhost sbin]# killall haproxy          或者kill -9 端口

监控页面
http://172.16.0.111:8888/stats

负载均衡测试

3、安装keepalived

[root@haproxy-master ~]# tar zxvf keepalived-1.2.7.tar.gz -C /usr/local/keepalived
[root@haproxy-master ~]# cd /usr/local/keepalived
[root@haproxy-master ~]# ./configure
[root@haproxy-master ~]# make && make install

编辑配置文件

[root@haproxy-master keepalived-1.2.23]# vim /usr/local/keepalived/etc/keepalived/keepalived.conf 
! Configuration File for keepalived

global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_instance VI_1 {
    state MASTER         #备服务器上改为BACKUP
    interface eth0
    virtual_router_id 51
    priority 100         #被服务器上改为小于100的数字，如99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.16.0.110          #虚拟ip，自己设定
    }
}

指定配置文件路径

[root@haproxy-master keepalived]# vim /usr/local/keepalived/etc/sysconfig/keepalived 
KEEPALIVED_OPTIONS="-D -f /usr/local/keepalived/etc/keepalived/keepalived.conf"

因为我们使用非默认路径（/usr/local）安装keepalived，需要设置一些软链接以保证keepalived能正常启动

[root@haproxy-master keepalived]# ln -s /usr/local/keepalived/sbin/keepalived  /usr/bin
[root@haproxy-master keepalived]# ln -s /usr/local/keepalived/etc/rc.d/init.d/keepalived  /etc/init.d/
[root@haproxy-master keepalived]# ln -s /usr/local/keepalived/etc/sysconfig/keepalived  /etc/sysconfig/

启动

[root@haproxy-master keepalived]# service keepalived start
Starting keepalived:                                       [  OK  ]
[root@haproxy-master keepalived]# chkconfig keepalived on

查看主服务器虚拟ip

[root@haproxy-master keepalived]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:ef:78:76 brd ff:ff:ff:ff:ff:ff
    inet 172.16.0.111/23 brd 172.16.1.255 scope global eth0
    inet 172.16.0.110/32 scope global eth0
    inet6 fe80::20c:29ff:feef:7876/64 scope link 
       valid_lft forever preferred_lft forever

测试vip是否正常提供服务，可以看到与master的监控界面一致

测试keepalived是否实现故障转移功能
停止master上的keepalived服务

[root@haproxy-master ~]# service keepalived stop
Stopping keepalived:                                       [  OK  ]

在backup上查看是否接管vip

[root@haproxy-backup sbin]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:6d:1a:b7 brd ff:ff:ff:ff:ff:ff
    inet 172.16.0.112/23 brd 172.16.1.255 scope global eth0
    inet 172.16.0.110/32 scope global eth0
    inet6 fe80::20c:29ff:fe6d:1ab7/64 scope link 
       valid_lft forever preferred_lft forever

再访问监控页面，可以看到

参考链接：
http://www.cnblogs.com/MacoLee/p/5853356.html
http://blog.csdn.net/aa168b/article/details/50372649
http://7424593.blog.51cto.com/7414593/1764640