构建高可用集群Keepalived+Haproxy负载均衡

重点概念
vrrp_script中节点权重改变算法
vrrp_script 里的script返回值为0时认为检测成功，其它值都会当成检测失败；
weight 为正时，脚本检测成功时此weight会加到priority上，检测失败时不加；
主失败:
主 priority < 从 priority + weight 时会切换。
主成功：
主 priority + weight > 从 priority + weight 时，主依然为主
weight 为负时，脚本检测成功时此weight不影响priority，检测失败时priority – abs(weight)
主失败:
主 priority – abs(weight) < 从priority 时会切换主从
主成功:
主 priority > 从priority 主依然为主

主要贴配置：VIP：10.16.37.198,10.16.37.199

web服务器IP：10.16.37.94,10.16.37.101

二台keepalived的IP：10.16.37.107,10.16.37.110

一台：

vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {

   notification_email {

         670196816@qq.com

   }

   notification_email_from admin@lnmp.com

   smtp_connect_timeout 3

   smtp_server 127.0.0.1

   router_id Iptables

}

vrrp_script chk_maintaince_down {

   script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"

   interval 1

   weight 2

}

vrrp_script chk_haproxy {

   script "killall -0 haproxy"

   interval 1

   weight 2

}

vrrp_instance VI_1 {

   interface eth0

   state MASTER

   priority 100

   virtual_router_id 125

   garp_master_delay 1

   authentication {

       auth_type PASS

       auth_pass 1e3459f77aba4ded

   }

   track_interface {

      eth0

   }

   virtual_ipaddress {

      10.16.37.198/22 dev eth0 label eth0:0

   }

   track_script {

      chk_haproxy

   }

   notify_master "/etc/keepalived/notify.sh master 10.16.37.198"

   notify_fault "/etc/keepalived/notify.sh fault 10.16.37.198"

}

vrrp_instance VI_2 {

   interface eth0

   state BACKUP

   priority 99

   virtual_router_id 126

   grap_master_delay 1

   authentication {

       auth_type pass

       auth_pass 7615c4b7f518cede

   }

   track_interface {

      eth0

   }

   virtual_ipaddress {

      10.16.37.199/22 dev eth0 label eth0:1

   }

   track_script {

      chk_haproxy

      chK_maintaince_down

   }

   notify_master "/etc/keepalived/notify.sh master 10.16.37.199"

   notify_backup "/etc/keepalived/notify.sh backup 10.16.37.199"

   notify_fault "/etc/keepalived/notify.sh fault 10.16.37.199"

}

　

另一台：

vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {

   notification_email {

         670196816@qq.com

   }

   notification_email_from admin@lnmp.com

   smtp_connect_timeout 3

   smtp_server 127.0.0.1

   router_id Iptables

}

vrrp_script chk_maintaince_down {

   script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"

   interval 1

   weight 2

}

vrrp_script chk_haproxy {

   script "killall -0 haproxy"

   interval 1

   weight 2

}

vrrp_instance VI_1 {

   interface eth0

   state BACKUP

   priority 99

   virtual_router_id 125

   garp_master_delay 1

   authentication {

       auth_type PASS

       auth_pass 1e3459f77aba4ded

   }

   track_interface {

      eth0

   }

   virtual_ipaddress {

      10.16.37.198/22 dev eth0 label eth0:1

   }

   track_script {

      chk_haproxy

   }

   notify_master "/etc/keepalived/notify.sh master 10.16.37.198"

   notify_fault "/etc/keepalived/notify.sh fault 10.16.37.198"

}

vrrp_instance VI_2 {

   interface eth0

   state MASTER

   priority 100

   virtual_router_id 126

   grap_master_delay 1

   authentication {

       auth_type pass

       auth_pass 7615c4b7f518cede

   }

   track_interface {

      eth0

   }

   virtual_ipaddress {

      10.16.37.199/22 dev eth0 label eth0:0

   }

   track_script {

      chk_haproxy

      chK_maintaince_down

   }

   notify_master "/etc/keepalived/notify.sh master 10.16.37.199"

   notify_backup "/etc/keepalived/notify.sh backup 10.16.37.199"

   notify_fault "/etc/keepalived/notify.sh fault 10.16.37.199"

}

脚本配置：

vi /etc/keepalived/notify.sh

#!/bin/bash

contact='root@localhost'

notify() {

    mailsubject="'hostname' to be $1: $2 floating"

    mailbody="'date '+%F %H:%M:%S'`: vrrp transition, `hostname` changed to be $1"

    echo $mailbody | mail -s "$mailsubject" $contact

}

case "$1" in

    master)

        notify master $2

        /etc/rc.d/init.d/haproxy restart

        exit 0

    ;;

    backup)

        notify backup $2

        exit 0

    ;;

    fault)

        notify fault $2

        exit 0

    ;;

    *)

        echo 'Usage: 'basename $0' {master|backup|fault}'

        exit 1

    ;;

Esac

Haproxy配置：

vi /etc/haproxy/haproxy.cfg

#---------------------------------------------------------------------

# Example configuration for a possible web application.  See the

# full configuration options online.

#

#   http://haproxy.1wt.eu/download/1.4/doc/configuration.txt

#

#---------------------------------------------------------------------

#---------------------------------------------------------------------

# Global settings

#---------------------------------------------------------------------

global

    # to have these messages end up in /var/log/haproxy.log you will

    # need to:

    #

    # 1) configure syslog to accept network log events.  This is done

    #    by adding the '-r' option to the SYSLOGD_OPTIONS in

    #    /etc/sysconfig/syslog

    #

    # 2) configure local2 events to go to the /var/log/haproxy.log

    #   file. A line like the following can be added to

    #   /etc/sysconfig/syslog

    #

    #    local2.*                       /var/log/haproxy.log

    #

    log         127.0.0.1 local2

    chroot      /var/lib/haproxy

    pidfile     /var/run/haproxy.pid

    maxconn     4000

    user        haproxy

    group       haproxy

    daemon

    # turn on stats unix socket

    stats socket /var/lib/haproxy/stats

#---------------------------------------------------------------------

# common defaults that all the 'listen' and 'backend' sections will

# use if not designated in their block

#---------------------------------------------------------------------

defaults

    mode                    http

    log                     global

    option                  httplog

    option                  dontlognull

    option http-server-close

    option forwardfor       except 127.0.0.0/8

    option                  redispatch

    retries                 3

    timeout http-request    10s

    timeout queue           1m

    timeout connect         10s

    timeout client          1m

    timeout server          1m

    timeout http-keep-alive 10s

    timeout check           10s

    maxconn                 3000

#---------------------------------------------------------------------

# main frontend which proxys to the backends

#---------------------------------------------------------------------

#frontend  main *:5000

#    acl url_static       path_beg       -i /static /images /javascript /stylesheets

#    acl url_static       path_end       -i .jpg .gif .png .css .js

#

#    use_backend static          if url_static

#    default_backend             app

#---------------------------------------------------------------------

# static backend for serving up images, stylesheets and such

#---------------------------------------------------------------------

#backend static

#    balance     roundrobin

#    server      static 127.0.0.1:4331 check

#---------------------------------------------------------------------

# round robin balancing between the various backends

#---------------------------------------------------------------------

#backend app

#    balance     roundrobin

#    server  app1 127.0.0.1:5001 check

#    server  app2 127.0.0.1:5002 check

#    server  app3 127.0.0.1:5003 check

#    server  app4 127.0.0.1:5004 check

listen stats

    mode http

    bind 0.0.0.0:1080

    stats enable

    stats refresh 30s

    maxconn 200

    stats hide-version

    stats uri     /haproxy-stats

    stats realm   Haproxy\ Statistics

    stats auth    admin:admin

    stats admin if TRUE

frontend http-in

    bind *:80

    mode http

    log global

    option httpclose

    option logasap

    option dontlognull

    capture request header Host len 20

    capture request header Referer len 60

    acl url_static path_beg -i /static /images /javascript /stylesheets

    acl url_static path_end         -i .jpg .jpeg .gif .png .css .js .html

    use_backend static_servers if url_static

    default_backend dynamic_servers

backend static_servers

    balance roundrobin

    server imgsrv1 10.16.37.101:80 check maxconn 6000

    server imgsrv2 10.16.37.94:80 check maxconn 6000

backend dynamic_servers

    balance source

    server websrv1 10.16.37.94:80 check maxconn 1000

server websrv2 10.16.37.101:80 check maxconn 1000

因为端口使用的是1080需要Iptables开启：

/sbin/iptables –I INPUT –p tcp –dport 1080 –j ACCEPT

/etc/rc.d/init.d/iptables save

Service iptables restart

Vi /etc/selinux/config

关闭selinux然后呢重启！！

二个server web采用nginx+双主mysql数据库，保证了web服务器的高可用性能，一台服务器宕机，另外一台立马连接！！

参考：

http://www.it165.net/admin/html/201405/2957.html