如何快速构建高可用集群(Keepalived+Haproxy+Nginx)

转自次元立方网：http://www.it165.net/admin/html/201405/2957.html

 另一篇：HA-Proxy+Nginx实现web负载均衡（haproxy篇）http://www.it165.net/admin/html/201405/3171.html

 

组件及实现的功能

Keepalived：实现对Haproxy服务的高可用，并采用双主模型配置;

Haproxy：实现对Nginx的负载均衡和读写分离;

Nginx：实现对HTTP请求的高速处理;

 

架构设计图

 

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

具体解释详见博文“Keepalived双主模型中vrrp_script中权重改变故障排查”

 

部署配置

Keepalived部署

配置

001.yum -yinstallkeepalived# 两节点都需部署
002.# 172.16.25.109
003.# vi /etc/keepalived/keepalived.conf
004.! Configuration Fileforkeepalived
005.global_defs {
006.   notification_email {
007.         root@localhost
008.   }
009.   notification_email_from [e-mail]
010.   smtp_connect_timeout 3
011.   smtp_server 127.0.0.1
012.   router_id LVS_DEVEL
013.}
014.vrrp_script chk_maintaince_down {
015.   script"[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
016.   interval 1
017.   weight 2
018.}
019.vrrp_script chk_haproxy {
020.    script"killall -0 haproxy"
021.    interval 1
022.    weight 2
023.}
024.vrrp_instance VI_1 {
025.    interface eth0
026.    state MASTER
027.    priority 100
028.    virtual_router_id 125
029.    garp_master_delay 1
030.    authentication {
031.        auth_type PASS
032.        auth_pass 1e3459f77aba4ded
033.    }
034.    track_interface {
035.       eth0
036.    }
037.    virtual_ipaddress {
038.        172.16.25.10/16 dev eth0 label eth0:0
039.    }
040.    track_script {
041.        chk_haproxy
042.    }
043.    notify_master"/etc/keepalived/notify.sh master 172.16.25.10"
044.    notify_fault"/etc/keepalived/notify.sh fault 172.16.25.10"
045.}
046.vrrp_instance VI_2 {
047.    interface eth0
048.    state BACKUP
049.    priority 99
050.    virtual_router_id 126
051.    garp_master_delay 1
052.    authentication {
053.        auth_type PASS
054.        auth_pass 7615c4b7f518cede
055.    }
056.    track_interface {
057.       eth0
058.    }
059.    virtual_ipaddress {
060.        172.16.25.11/16 dev eth0 label eth0:1
061.    }
062.    track_script {
063.        chk_haproxy
064.chk_maintaince_down
065.    }
066.    notify_master"/etc/keepalived/notify.sh master 172.16.25.11"
067.    notify_backup"/etc/keepalived/notify.sh backup 172.16.25.11"
068.    notify_fault"/etc/keepalived/notify.sh fault 172.16.25.11"
069.}
070.# 172.16.25.110
071.# vi /etc/keepalived/keepalived.conf
072.! Configuration Fileforkeepalived
073.global_defs {
074.   notification_email {
075.         root@localhost
076.   }
077.   notification_email_from [e-mail]
078.   smtp_connect_timeout 3
079.   smtp_server 127.0.0.1
080.   router_id LVS_DEVEL
081.}
082.vrrp_script chk_maintaince_down {
083.   script"[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
084.   interval 1
085.   weight 2
086.}
087.vrrp_script chk_haproxy {
088.    script"killall -0 haproxy"
089.    interval 1
090.    weight 2
091.}
092.vrrp_instance VI_1 {
093.    interface eth0
094.    state BACKUP
095.    priority 99
096.    virtual_router_id 125
097.    garp_master_delay 1
098.    authentication {
099.        auth_type PASS
100.        auth_pass 1e3459f77aba4ded
101.    }
102.    track_interface {
103.       eth0
104.    }
105.    virtual_ipaddress {
106.        172.16.25.10/16 dev eth0 label eth0:0
107.    }
108.    track_script {
109.        chk_haproxy
110.chk_maintaince_down
111.    }
112.    notify_master"/etc/keepalived/notify.sh master 172.16.25.10"
113.    notify_backup"/etc/keepalived/notify.sh backup 172.16.25.10"
114.    notify_fault"/etc/keepalived/notify.sh fault 172.16.25.10"
115.}
116.vrrp_instance VI_2 {
117.    interface eth0
118.    state MASTER
119.    priority 100
120.    virtual_router_id 126
121.    garp_master_delay 1
122.    authentication {
123.        auth_type PASS
124.        auth_pass 7615c4b7f518cede
125.    }
126.    track_interface {
127.       eth0
128.    }
129.    virtual_ipaddress {
130.        172.16.25.11/16 dev eth0 label eth0:1
131.    }
132.    track_script {
133.        chk_haproxy
134.    }
135.    notify_master"/etc/keepalived/notify.sh master 172.16.25.11"
136.    notify_backup"/etc/keepalived/notify.sh backup 172.16.25.11"
137.    notify_fault"/etc/keepalived/notify.sh fault 172.16.25.11"
138.}
139.# vi /etc/keepalived/notify.sh
140.#!/bin/bash
141.# Author: Jason.Yu <[e-mail]>
142.# description: An example of notify script
143.#
144.contact='root@localhost'
145.notify() {
146.    mailsubject="`hostname` to be $1: $2 floating"
147.    mailbody="`date '+%F %H:%M:%S'`: vrrp transition, `hostname` changed to be $1"
148.    echo$mailbody | mail -s "$mailsubject"$contact
149.}
150.case"$1"in
151.    master)
152.        notify master $2
153.        /etc/rc.d/init.d/haproxy restart
154.        exit0
155.    ;;
156.    backup)
157.        notify backup $2# 在节点切换成backup状态时，无需刻意停止haproxy服务，防止chk_maintaince和chk_haproxy多次对haproxy服务操作；
158.        exit0
159.    ;;
160.    fault)
161.        notify fault $2# 同上
162.        exit0
163.    ;;
164.    *)
165.        echo'Usage: `basename $0` {master|backup|fault}'
166.        exit1
167.    ;;
168.esac

启动服务

1.service keepalived start# 在两个节点上都需要启动

keepalived双主模型启动

Haproxy部署

安装配置

01.yum -yinstallhaproxy# 两节点都需部署
02.vi/etc/haproxy/haproxy.cfg# 两节点配置一致
03.global
04.    log         127.0.0.1 local2
05.    chroot      /var/lib/haproxy
06.    pidfile     /var/run/haproxy.pid
07.    maxconn     4000
08.    user         haproxy
09.    group       haproxy
10.    daemon# 以后台程序运行；
11.defaults
12.    mode                   http# 选择HTTP模式，即可进行7层过滤；
13.    log                     global
14.    option                  httplog# 可以得到更加丰富的日志输出；
15.    option                  dontlognull
16.    option http-server-close# server端可关闭HTTP连接的功能；
17.    option forwardfor except 127.0.0.0/8# 传递client端的IP地址给server端，并写入“X-Forward_for”首部中；
18.    option                  redispatch
19.    retries                 3
20.    timeout http-request    10s
21.    timeout queue           1m
22.    timeout connect         10s
23.    timeout client          1m
24.    timeout server          1m
25.    timeout http-keep-alive 10s
26.    timeout check           10s
27.    maxconn                 30000
28.listen stats
29.    modehttp
30.    bind0.0.0.0:1080# 统计页面绑定1080端口；
31.    statsenable# 开启统计页面功能；
32.    stats hide-version# 隐藏Haproxy版本号；
33.    stats uri     /haproxyadmin?stats# 自定义统计页面的访问uri；
34.    stats realm   Haproxy\ Statistics# 统计页面密码验证时的提示信息；
35.    stats auth    admin:admin# 为统计页面开启登录验证功能；
36.    stats adminifTRUE# 若登录用户验证通过，则赋予管理功能；
37.frontend http-in
38.    bind*:80
39.    mode http
40.    log global
41.    option httpclose
42.    option logasap
43.    option dontlognull
44.    capture request  header Host len 20
45.    capture request  header Referer len 60
46.    acl url_static       path_beg       -i /static /images /javascript /stylesheets
47.    acl url_static       path_end       -i .jpg .jpeg .gif .png .css .js .html
48.    use_backend static_serversifurl_static# 符合ACL规则的，请求转入后端静态服务器
49.    default_backend dynamic_servers# 默认请求转入后端动态服务器
50.backend static_servers
51.    balance roundrobin
52.    server imgsrv1 192.168.0.25:80 check maxconn 6000# 静态服务器，可配置多台，还可设置权重weight；
53.backend dynamic_servers
54.    balancesource# 对于动态请求利用source调度算法，可一定程度上实现session保持；但最好利用cookie绑定的方式实现session保持
55.    server websrv1 192.168.0.35:80 check maxconn 1000# 动态服务器，可配置多台，还可设置权重weight；

启动服务

1.service haproxy start# 两节点都需要启动

Nginx部署

见博客“如何测试Nginx的高性能”http://www.it165.net/admin/html/201405/2928.html

 

访问验证

Haproxy统计页面测试

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动静分离测试

 

高可用测试