HAproxy指南之haproxy双机热备 (案例篇)

3ewsd

　　   haproxy的出现正是弥补nginx一些应用上不足，比如session会话保持，健康监控检测机制，负载算法等等，在很多应用环境中，nginx的代理性能会haproxy稍逊一些，不过在一些实际案例中，keepalive+nginx与keepalive+nginx往往会根据业务去选择，比如nginx有着haproxy没有的代理缓存的功能等等，如果需要用到缓存就可以使用nginx，总之:根据业务来选择这两者！
Keepalive+haproxy双机热备
如图所示为整体的拓扑图：
　　

一.部署前说明：
(1)系统版本: centos 6.6（64位）
(2)角色及ip相关信息:

角色名称	网络ip信息
客户端(CIP)	10.58.137.203/24
Master_DR	eth0:172.51.96.105/24 &&  eth1:192.168.0.105/24
Backup_DR	eth0:172.51.96.119/24 &&  eth1:192.168.0.119/24
VIP	172.51.96.175/24

(3)相关中间件信息
keepalive版本信息: keepalived-1.2.15
nginx版本信息:  haproxy-1.5.15  （提供proxy代理）
　　二.部署操作：

haproxy部署
分别在Master_DR和backup_DR上安装haproxy，操作如下：
　　1.1 到haproxy官网下载haproxy源码包如下
cd ~
wget http://www.haproxy.org/download/1.5/src/haproxy-1.5.15.tar.gz
　　1.2 创建haproxy运行用户

　　
groupadd -r haproxy
useradd -r -g haproxy -M -s /sbin/nologin haproxy
　　1.3 编译安装haproxy：
　　
cd ~
tar zxvf haproxy-1.5.15.tar.gz -C /usr/local/src
cd /usr/local/src/haproxy-1.5.15
make TARGET=linux26 PREFIX=/usr/local/haproxy
make install PREFIX=/usr/local/haproxy
　　注意：TARGET=Linux26 是通过uname -a 来查看Linux内核版本的
　　1.4 创建haproxy主配置文件：
mkdir /etc/haproxy/
vim /etc/haproxyhaproxy.cfg配置代码内容如下：（注意主备server上haproxy.cfg配置要一致）


#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
        log 127.0.0.1   local3            
        maxconn 204800
        chroot /usr/local/haproxy
        user  haproxy
        group haproxy
        daemon
        nbproc 1
        pidfile /var/run/haproxy.pid
        stats socket /usr/local/haproxy/stats
        description haproxy server
#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------
defaults
        log     global
        mode    http
        maxconn 10000
        option  httplog
        option  httpclose
        option  dontlognull
        option  forwardfor      except 127.0.0.0/8
        retries 3
        option redispatch
        option abortonclose
        balance roundrobin
        timeout http-request    10s
        timeout queue           1m
        timeout connect         10s
        timeout client          1m
        timeout server          1m
        timeout http-keep-alive 10s
        timeout check           10s
#---------------------------------------------------------------------
# use listen setting the haproxy status for site
#---------------------------------------------------------------------
listen admin_status     
        bind *:3030
        mode http
        log 127.0.0.1 local3 err
        stats refresh 5s
        stats uri /status   
        stats realm www.skeryp.com
        stats auth admin:admin
        stats hide-version
        stats admin if TRUE
#---------------------------------------------------------------------
# main listen which proxys to the backends
#---------------------------------------------------------------------
listen  www
        bind *:80
        maxconn 5000
        mode http
        log global
        option httplog
        option httpclose
        option forwardfor
        log         global
        default_backend default  
#
backend default
        mode http
        option  httpchk GET /index.html
        server default 127.0.0.1:81 cookie id1 check inter 2000 rise 2 fall 3 maxconn 50001.5 创建haproxy系统服务启动脚本：
关于haproxy服务脚本代码请访问:http://blief.blog.运维网.com/6170059/1750573
1.6 启动haproxy服务：

server haproxy restart

Keepalive部署
(1)分别在Master_DR和backup_DR上安装keepalive，操作如下：
1. 安装Keepalive所需要的相关依赖包:
yum install openssl-devel popt-devel libnl-devel kernel-devel  -y
　　2. 编译安装keepalive

1.1 keepalived的源码获取
keepalived源码包我们可以到keepalived的官网:http://www.keepalived.org/去下载，相关说明文档亦可在其官网查看，比如keepalived的使用，相关配置说明，这里演示的版本为:1.2.15
cd ~
wget http://www.keepalived.org/software/keepalived-1.2.15.tar.gz
1.2 编译安装keepalived



ln -s /usr/src/kernels/2.6.32-573.18.1.el6.x86_64/ /usr/src/linux
tar zxvf keepalived-1.2.15.tar.gz -C /usr/local/src
cd /usr/local/src/keepalived-1.2.15/
./configure \
--prefix=/usr/local/keepalived \
--with-kernel-dir=/usr/src/kernels/2.6.32-573.18.1.el6.x86_64
#2.6.32-573.18.1.el6.x86_64 这个需要根据kernel来匹配，一般安装了kernel-devel即可查看
make  make install


cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/


cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
chkconfig --add keepalived
chkconfig --level 2345 keepalived on


mkdir -p /etc/keepalived
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived(3)分别配置Master_DR以及Backup_DR上的keepalive实例，如下所示:
1. master_dr配置代码示例（主调度器）

vim /etc/keepalived/keepalived.conf内容如下
! Configuration File for keepalived
global_defs {
   notification_email {
       admin@bluemobi.cn
   }
   notification_email_from  lvs_admin@bluemobi.cn
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id DR_MASTER
}
vrrp_script check_haproxy {                              #表示创建一个脚本check_haproxy
   script "/etc/keepalived/scripts/check_haproxy.sh"     #引用的脚本路径
   interval 3                                          #表示检测时间的间隔为3s
}
vrrp_instance http {
    state BACKUP
    interface eth0   
    dont_track_primary
    nopreempt                        #不抢占master
    track_interface {                #表示需要检测的网卡
    eth0
    eth1
    }
    mcast_src_ip 172.51.96.105       #表示设置组播的源地址
    garp_master_delay 6
    virtual_router_id 60
    priority 110
    advert_int 1
    authentication {
    auth_type PASS
    autp_pass 1234
    }
    virtual_ipaddress {
    172.51.96.175/24 brd  172.51.96.255 dev eth0 label eth0:1
    }
    virtual_routes {
    172.51.96.175/24 dev eth0
    }
    track_script {
    check_haproxy
    }
    notify_master /etc/keepalived/scripts/state_master.sh
    notify_backup /etc/keepalived/scripts/state_backup.sh
    notify_fault  /etc/keepalived/scripts/state_fault.sh
}
2. backup_dr配置示例（备调度器）

vim /etc/keepalived/keepalived.conf内容如下
! Configuration File for keepalived
global_defs {
   notification_email {
       admin@bluemobi.cn
   }
   notification_email_from  admin@bluemobi.cn
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id DR_BACKUP
}
vrrp_script check_haproxy {
   script "/etc/keepalived/scripts/check_haproxy.sh"
   interval 3
}
vrrp_instance http {
    state BACKUP
    interface eth0
    dont_track_primary
    track_interface {
    eth0
    eth1
    }
    mcast_src_ip 172.51.96.119
    garp_master_delay 6
    virtual_router_id 60
    priority 105
    advert_int 1
    authentication {
    auth_type PASS
    autp_pass 1234
    }
    virtual_ipaddress {
    172.51.96.175/24 brd  172.51.96.255 dev eth0 label eth0:1
    }
    virtual_routes {
    172.51.96.175/24 dev eth0
    }
    track_script {
    check_haproxy
    }
    notify_master /etc/keepalived/scripts/state_master.sh
    notify_backup /etc/keepalived/scripts/state_backup.sh
    notify_fault  /etc/keepalived/scripts/state_fault.sh
}3.分别在主调度server和备调度server编写以下脚本，如下：
　　i 当调度器为切换master server时，记录切换时间日志
　　vim /etc/keepalived/scripts/state_master.sh
代码如下:
#!/bin/bash
echo -e  >> $LOGFILE
host=CN-SH-DR01      #设置当前的主机名
LOGFILE="/var/log/keepalived-state.log"
echo "[Master]" >> $LOGFILE
date >> $LOGFILE
echo "The ${host}  Starting to become master server...." >> $LOGFILE 2>&1
echo "Please run the “ipvsadm -Ln”  check the keepalived state ..." >> $LOGFILE
echo ".........................................................................!">> $LOGFILE
echo >>$LOGFILE
ii 当调度器为切换backup server时，记录切换时间日志
vim /etc/keepalived/scripts/state_backup.sh
代码如下:
#!/bin/bash
echo -e >> $LOGFILE
host=CN-SH-DR01     #设置当前的主机名
LOGFILE="/var/log/keepalived-state.log"
echo "[Backup]" >> $LOGFILE
date >> $LOGFILE
echo "The ${host}  Starting to become Backup server...." >> $LOGFILE 2>&1
echo "Please run the “ipvsadm -Ln”  check the state ..." >> $LOGFILE
echo "........................................................................!">> $LOGFILE
echo  >> $LOGFILEiii  当调度器出现错误时，记录错误时间日志
vim /etc/keepalived/scripts/state_fault.sh
代码如下:
#!/bin/bash
echo -e >> $LOGFILE
host=CN-SH-DR01      #设置当前的主机名
LOGFILE="/var/log/keepalived-state.log"
echo "[fault errot ]" >> $LOGFILE
date >> $LOGFILE
echo "The ${host}  is fault error...." >> $LOGFILE 2>&1
echo "Please check the server state ..." >> $LOGFILE
echo "........................................................................!">> $LOGFILE
echo  >> $LOGFILEiiii 服务状态健康监测脚本,比如当haproxy不可用时，及时切换到backup调度器上
vim /etc/keepalived/scripts/check_haproxy.sh
#!/bin/bash
#nginx="/usr/local/haproxy/sbin/haproxy"
PID=`ps -C haproxy --no-heading|wc -l`
if [ "${PID}" = "0" ];
    then
         /etc/init.d/haproxy start
    sleep 3
    LOCK=`ps -C haproxy --no-heading|wc -l`
    if [ "${LOCK}" = "0" ];
    then
        /etc/init.d/keepalived stop
    fi
fi(4)依次重启master_dr,backup-dr上keepalive服务

# service keepalived restart

三.测试验证：
在两台调度器安装web服务并创建相关测试页，如下：
master-dr主调度服务器的测试页面
[root@master-dr www]# curl 172.51.96.105:81
this is master server
[root@master-dr www]#backup-dr备调度服务器的测试页面
[root@backup-dr htdocs]# curl 172.51.96.119:81
this is backup server
[root@backup-dr htdocs]#通过messages查看vip抢夺情况，如下所示:

　　

　　述上发现vip已经被master-dr抢夺，通过ifconfig看到master-dr已经存在vip地址，如下

　　

　　在客户端通过:http://vip 就可以访问到页面，此时访问的是master-dr的页面：

　　

　　我们在master-dr将keepalived服务停止掉，来模仿主调度器宕机情形：

[root@master-dr scripts]# service keepalived stop
Stopping keepalived:                                       [  OK  ]
[root@master-dr scripts]#
　　

　　分别查看master-dr和backup-dr的keepalive日志：

　　

　　此时vip已经由backup-dr接管了，因为master-dr上nginx服务异常，而keepalive会定时触发引用的检查脚本
“check_nginx”检查nginx状态，发现nginx可用就停止了keepalive服务，从而使vip顺利的飘逸到backup-dr上；
　　 查看keepalive-state.log,可以看到master-dr和backup-dr会记录每个状态的的信息：同时日志记录脚本也会记录相关信息：
[root@master-dr sbin]# tail -10  /var/log/keepalived-state.log
The CN-SH-DR01  Starting to become Backup server....
Please run the “ipvsadm -Ln”  check the state ...
...............................................................................!
[fault errot ]
Fri Mar 11 15:28:48 CST 2016
The CN-SH-DR01  is fault error....
Please check the server state ...
...............................................................................![root@backup-dr htdocs]# tail -10 /var/log/keepalived-state.log
[Backup]
Fri Mar 11 14:42:56 CST 2016
The CN-SH-DR02  Starting to become Backup server....
Please run the “ipvsadm -Ln”  check the state ...
...............................................................................!
[Master]
Fri Mar 11 15:06:58 CST 2016
The CN-SH-DR02  Starting to become master server....
Please run the “ipvsadm -Ln”  check the state ...
...............................................................................!　　

　　再次访问http://vip 发现页面为backup-dr的页面：

　　

　　到这里，整个keepalive+haproxy双机热备就部署完成了
　　

　　总结:关于keepalive+haproxy双机热备适合很多web前端高可用集群应用，相对于keepalive+lvs案例应用，配置起来更方便，更简单，与它同样的经典应用案例：keepalive+nginx也是一个不错的双机热备方案，通常在需要高性能高可用反向代理场合，keepalive+haproxy是一个不错的选择方案。