用HAProxy和KeepAlived构建高可用的反向代理

 

用HAProxy和KeepAlived构建高可用的反向代理

用HAProxy和KeepAlived构建高可用的反向代理 前言对于访问量较大的网站来说，随着流量的增加单台服务器已经无法处理所有的请求，这时候需要多台服务器对大量的请求进行分流处理，即负载均衡。而如果实 现负载均衡，必须在网站的入口部署服务器（不只是一台）对这些请求进行分发，这台服务器即反向代理。由于反向代理服务器是网站的入口，其负载压力大且易遭 到攻击，存在单点故障的风险，所以我们需要一个高可用的方案来实现当一台反向代理服务器宕机的时候，另一台服务器会自动接管服务。基于以上要求，我们使用 HAProxy，KeepAlived来构建高可用的反向代理系统。 介绍HAProxy是高性能的代理服务器，其可以提供7层和4层代理，具有healthcheck，负载均衡等多种特性，性能卓越，国内很多大的互联网公 司都在使用， KeepAlived是一个高可用方案，通过VIP(即虚拟IP)和心跳检测来实现高可用。其原理是存在一组（两台）服务器，分别赋予 Master,Backup两个角色，默认情况下Master会绑定VIP到自己的网卡上，对外提供服务。Master,Backup会在一定的时间间隔 向对方发送心跳数据包来检测对方的状态，这个时间间隔一般为2秒钟，如果Backup发现Master宕机，那么Backup会发送ARP包到网关，把 VIP绑定到自己的网卡，此时Backup对外提供服务，实现自动化的故障转移，当Master恢复的时候会重新接管服务。

部署环境准备

环境OS: CentOS Linux release 6.0 (Final) 2.6.32-71.29.1.el6.x86_64

HAProxy: 1.5.10

KeepAlived: 1.2.2

VIP: 192.168.36.100

M: 192.168.36.154

S: 192.168.36.129

架构

                   192.168.36.100
             +-----------VIP----------+   
             |                        |
             |                        |
           Master                   Backup
        192.168.36.129            192.168.36.154
        +----------+             +----------+
        | HAProxy  |             | HAProxy  |
        |keepalived|             |keepalived|
        +----------+             +----------+
             |  
             v  
    +--------+---------+ 
    |        |         |
    |        |         |
    v        v         v
+------+  +------+  +------+
| WEB1 |  | WEB2 |  | WEB3 |
+------+  +------+  +------+

安装HAProxy

安装pcre

 yum install pcre
 wget wget http://www.haproxy.org/download/1.5/src/haproxy-1.5.10.tar.gz
 tar -zxvf haproxy-1.5.10.tar.gz
 cd haproxy-1.5.10

注意编译参数： 
TARGET是指自己系统的内核版本 ARCH指定系统是32位还是64位 
CPU=native: use the build machine's specific processor optimizations 
更多编译参数内容见源码中的README 
 make TARGET=linux26 make TARGET=linux26 USE_OPENSSL=1 ADDLIB=-lz  #编译支持ssl认证功能，haproxy 1.5t版本以上才支持。
 make install
 ln -s /usr/local/src/haproxy-1.5.10 /usr/local/haproxy
 mkdir /usr/local/haproxy/etc

配置文件hparoxy

cd haproxy-1.5.10

cat etc/haproxy.cfg

global
    log 127.0.0.1   local3 info
    maxconn 20000   
    user lashourun 
    group lashourun
    chroot /var/chroot/haproxy
    daemon 
    nbproc 4

defaults
   log     127.0.0.1       local3
   mode    http            
   option  httplog
   option  httpclose
   option  dontlognull
   option  forwardfor
   option accept-invalid-http-request 
   retries 2
   balance roundrobin 
   stats enable
   stats   uri   /admin
   stats  auth haadmin:lashoupay
   timeout http-request 20s
   timeout connect 50000
   timeout client 500000
   timeout server 500000

frontend lashoupay-http #支持http 80端口访问的业务
    bind *:80
    reqadd X-Forwarded-Proto: http
    #acl lashoupay-4.90 dst 192.168.4.90
    acl lashoupay-4.90 path_beg /lashoupay/lashoupay || dst 192.168.4.90
    acl vs-lashoupay-index-4.94 dst 192.168.4.111
    #acl vs-lsmvas-4.51 dst 192.168.4.51
    #acl vs-lsmvas-4.93 dst 192.168.4.93
    acl vs-pay-4.90 dst  192.168.4.114
    acl vs-project-4.95 dst 192.168.4.115
    use_backend lashoupay-4.90-pool if lashoupay-4.90
    use_backend vs-lashoupay-index-4.94-pool if vs-lashoupay-index-4.94
    #use_backend vs-lsmvas-4.51-pool if vs-lsmvas-4.51
    #use_backend vs-lsmvas-4.93-pool if vs-lsmvas-4.93
    use_backend vs-pay-4.90-pool if vs-pay-4.90
    use_backend vs-project-4.95-pool if vs-project-4.95

frontend lashoupay-https #支持https 443 ssl认证访问的业务

    bind *:443 ssl crt /usr/local/haproxy/cert.pem
    option httpclose
    option forwardfor
    reqadd X-Forwarded-Proto: https
    default_backend lashoupay-4.90-pool
frontend vs-lsmvas4.51-9002  #支持一些特殊业务端口访问
    mode http
    bind *:9002
    reqadd X-Forwarded-Proto: http
    acl vs-lsmvas-4.51 dst 192.168.4.51
    acl vs-lsmvas-4.93 dst 192.168.4.93
    use_backend vs-lsmvas-4.51-pool if vs-lsmvas-4.51
    use_backend vs-lsmvas-4.93-pool if vs-lsmvas-4.93

backend lashoupay-4.90-pool
    redirect scheme https if !{ ssl_fc }
    balance roundrobin
        stats refresh 2
        server lashoupay-4.73 192.168.4.73:80 weight 3 maxconn 10000 check

backend vs-lashoupay-index-4.94-pool
    balance roundrobin
    stats refresh 2
    server lashoupay-index-16-26 192.168.4.16:9002 weight 3 maxconn 10000 check

backend vs-lsmvas-4.51-pool
    balance roundrobin
    stats refresh 2
    #server vs-lsmvas-4.16 192.168.4.16:9002 weight 3 maxconn 10000 check
    server vs-lsmvas-4.18 192.168.4.18:9002 weight 3 maxconn 10000 check
    server vs-lsmvas-4.26 192.168.4.26:9002 weight 3 maxconn 10000 check
    server vs-lsmvas-4.28 192.168.4.28:9002 weight 3 maxconn 10000 check


backend vs-lsmvas-4.93-pool
    balance roundrobin
    stats refresh 2
    server vs-lsmvas-4.18 192.168.4.18:9002 weight 3 maxconn 10000 check
    server vs-lsmvas-4.28 192.168.4.28:9002 weight 3 maxconn 10000 check

backend vs-pay-4.90-pool
    balance roundrobin
    stats refresh 2
    #server vs-lsmvas-4.16 192.168.4.16:9002 weight 3 maxconn 10000 check
    server vs-lsmvas-4.18 192.168.4.18:9002 weight 3 maxconn 10000 check
    server vs-lsmvas-4.26 192.168.4.26:9002 weight 3 maxconn 10000 check
    server vs-lsmvas-4.28 192.168.4.28:9002 weight 3 maxconn 10000 check

backend vs-project-4.95-pool
    balance roundrobin
    stats refresh 2
    server project-4.17 192.168.4.17:9002 weight 3 maxconn 10000 check
    server project-4.27 192.168.4.27:9002 weight 3 maxconn 10000 check

查看HAProxy的状态：http://192.168.36.100/haproxy-stats，这个页面会显示HAProxy本身以及后端服务器的状态。

日志haproxy会把日志记录发送到syslog server(CentOS6下是rsyslogd，UDP514端口)， 编辑/etc/rsyslog.conf文件，添加如下内容：

ModLoad imudp
UDPServerRun 514
UDPServerAddress 127.0.0.1
local3.*                /var/log/haproxy.log

重启rsyslog

 /etc/init.d/rsyslog restart

自动轮转日志，编辑/etc/logrotate.d/haproxy.cfg，添加如下内容：

/var/log/haproxy.log
{
    rotate 4
    daily
    missingok
    notifempty
    compress
    delaycompress
    sharedscripts
    postrotate
    reload rsyslog > /dev/null 2>&1 || true
    endscript
}

启动脚本

 wget -O haproxy https://raw.github.com/gist/3665034/4125bd5b81977a72e5eec30650fb21f3034782a0/haproxy-init.d 
 cp haproxy /etc/init.d/haproxy
 chmod +x /etc/init.d/haproxy
#使用方式
 /etc/init.d/haproxy start|stop|restart

安装KeepAlived

安装依赖库

 yum install popt popt-devel
 wget http://www.keepalived.org/software/keepalived-1.2.2.tar.gz
 tar -zxvf keepalived-1.2.2.tar.gz
 cd keepalived-1.2.2
 ./configure --prefix=/usr/local/keepalived
 make && make install

 cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/keepalived
 cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
 cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
 mkdir -p /etc/keepalived/
 cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf 
 chmod +x /etc/init.d/keepalived

使用方式

 /etc/init.d/keepalived start|stop|restart

Master服务器上的配置

cat etc/keepalived/keepalived.conf
global_defs {

   notification_email {
       user@example.com
   }

   notification_email_from mail@example.org
   smtp_server 192.168.x.x
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

#监测haproxy进程状态，每2秒执行一次
vrrp_script chk_haproxy {
    script "/usr/local/keepalived/chk_haproxy.sh"
    interval 2
    weight 2
}

vrrp_instance VI_1 {
    state MASTER #标示状态为MASTER
    interface eth0
    virtual_router_id 51
    priority 101   #MASTER权重要高于BACKUP
    advert_int 1
    mcast_src_ip 192.168.36.129 #Master服务器IP

    authentication {
        auth_type PASS #主从服务器验证方式
        auth_pass 1111
    }

    track_script {
        chk_haproxy #监测haproxy进程状态
    }

    #VIP
    virtual_ipaddress {
        192.168.36.100 #虚拟IP
    }
}

Bakcup服务器上的配置

cat etc/keepalived/keepalived.conf
global_defs {
   notification_email {
   user@example.com
   }

   notification_email_from mail@example.org
   smtp_server 192.168.x.x
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

#监测haproxy进程状态，每2秒执行一次
vrrp_script chk_haproxy {
    script "/usr/local/keepalived/chk_haproxy.sh"
    interval 2
    weight 2
}

vrrp_instance VI_1 {
    state BACKUP #状态为BACKUP
    interface eth0
    virtual_router_id 51
    priority 100  #权重要低于MASTER
    advert_int 1
    mcast_src_ip 192.168.36.154 #Backup服务器的IP

    authentication {
        auth_type PASS
        auth_pass 1111
    }

    track_script {
        chk_haproxy #监测haproxy进程状态
    }

    #VIP
    virtual_ipaddress {
        192.168.36.100 #虚拟IP
    }
}

• keepalived 配置中引用的脚本 chk_haproxy.sh内容

#!/bin/bash
#
# author: weizhifeng
# description: 
# 定时查看haproxy是否存在，如果不存在则启动haproxy，
# 如果启动失败，则停止keepalived
# 
status=(ps aux|grep haproxy | grep -v grep | grep -v bash | wc -l)
if [ "{status}" = "0" ]; then
    /etc/init.d/haproxy start

    status2=(ps aux|grep haproxy | grep -v grep | grep -v bash |wc -l)

    if [ "{status2}" = "0"  ]; then
            /etc/init.d/keepalived stop
    fi
fi

高可用测试

• 1. 在Master上停止keepalived，查看系统日志，发IP

  /etc/init.d/keepalived stop
  tail -f /var/log/message
 Keepalived: Terminating on signal Keepalived: Stopping Keepalived v1.2.2 (11/03,2011) 
 Keepalived_vrrp: Terminating VRRP child process on signal 
 Keepalived_vrrp: VRRP_Instance(VI_1) removing protocol VIPs.

• 2. 在Backup上查看系统日志，发现Backup已经进入MASTER角色，并且绑定了VIP 192.168.36.100

  tail -f /var/log/message
 Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE
 Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs
 Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.36.100 #在Backup上查看VIP是否已经绑定

• 3. 在Master上重新启动keepalived，查看系统日志，发现重新获得MASTER角色，并且绑定VIP 192.168.36.100

  /etc/init.d/keepalived start
  tail -f /var/log/message
 Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE
 Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE
 Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.
 Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.36.100

• 4. 在Backup上查看系统日志，发现其重新回到BACKUP角色，并且释放VIP

  tail -f /var/log/message
 Keepalived_vrrp: VRRP_Instance(VI_1) Received higher prio advert
 Keepalived_vrrp: VRRP_Instance(VI_1) Entering BACKUP STATE
 Keepalived_vrrp: VRRP_Instance(VI_1) removing protocol VIPs.

• 并发测试我们使用webbench来对HAProxy进行并发测试

 yum install ctags
 wget http://home.tiscali.cz/~cz210552/distfiles/webbench-1.5.tar.gz
 tar -zxvf webbench-1.5.tar.gz
 cd webbench-1.5
 make 
 mkdir -p /usr/local/man && make install

测试方法：

 webbench -c 100 -t 3000 http://192.168.36.100/index.html

haproxy维护

• 1,haproxy做前端代理，出错类 -1/-1/-1/-1/0 400 187 - - PR-- 0/0/0/0/0 0/0 "

  google了一下全是英文的，大概意思说原因是因为客户端发来了无效的字符，处理不了罢，说白了，就是可能不支持客户发来的字符集，

  我们查了一下发来的字符串中文的，好像是gb2312的，google有牛人给出的解决办法如下：

  打开haproxy.cfg配置加上如下

  timeout http-request 20s

  option accept-invalid-http-request