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