说到Linux下的负载均衡，其实有很多服务是可以实现的，比如：haproxy，lvs，nginx，这些服务都可以做负载均衡，而我们今天主要介绍的是Haproxy实现Apache的负载均衡。一般做法是通过Haproxy+Keeplive实现高可用负载均衡的，我们将会在后面的文章介绍。
目的：访问Haproxy自动轮询分配后台服务器
环境介绍：
Hostname：A-S
IP:192.168.5.21
Role：Apache
Hostname：B-S
IP:192.168.5.22
Role：Apache
Hostname：C-S
IP:192.168.5.23
Role：Haproxy
我们先看看安装完默认的Haproxy的配置介绍：
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vim /etc/haproxy/haproxy.cfg
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global
log 127.0.0.1 local2
chroot /var/lib/haproxy
pidfile /var/run/haproxy.pid
maxconn 4000
user haproxy
group haproxy
daemon
stats socket /var/lib/haproxy/stats
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
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
backend static
balance roundrobin
server static 127.0.0.1:4331 check
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
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接下来我们开始正式环境配置介绍：首先是安装Apache服务，然后配置显示页面：
安装完成
查看httpd 版本
接下来我们首先要为apache定义一个 默认的页面，方便区分
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Vim /var/www/httml/index.html
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</html>
<!DOCTYPE html>
<html>
<head>
<title>Welcome to Apache</title>
<style>
body {
35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
<style type="text/css">
h1{color:red}
h2{color:blue}
h3{color:green}
h4{color:yellow}
}
</style>
</head><body bgcolor='#46A3FF'>
<h1>Welcome to A-S Apache</h1>
<h2>HostName:A-S</h2>
<h3>IP:192.168.5.21</h3>
<h4>Service:Apache</h4>
<input type=button value="Refresh" onclick="window.location.href('http://192.168.5.21')">
</body>
</html>
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启动服务
然后添加默认的防火墙端口8o
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Firewall-cmd --zone=public --add-port='80/tcp' --permanent
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或者vim /etc/firewalld/zone/public.xml
添加一下格式
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<port portocal='tcp' port='80'>
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接下来我们在本地访问测试一下
接下来我们也同样按照方法部署第二台apache服务，方法跟上面完全一样
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</html>
<!DOCTYPE html>
<html>
<head>
<title>Welcome to Apache</title>
<style>
body {
35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
<style type="text/css">
h1{color:red}
h2{color:blue}
h3{color:green}
h4{color:yellow}
}
</style>
</head><body bgcolor='#CA8EFF'>
<h1>Welcome to B-S Apache</h1>
<h2>HostName:B-S</h2>
<h3>IP:192.168.5.22</h3>
<h4>Service:Apache</h4>
<input type=button value="Refresh" onclick="window.location.href('http://192.168.5.22')">
</body>
</html>
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测试访问
最后我们开始部署haproxy了
我们使用192.168.5.33来部署haproxy了
我们可以编辑haproxy的默认配置文件
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vim /etc/haproxy/haproxy.nfg
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global
log 127.0.0.1 local2
chroot /var/lib/haproxy
pidfile /var/run/haproxy.pid
maxconn 4000
user haproxy
group haproxy
daemon
stats socket /var/lib/haproxy/stats
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
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
backend static
balance roundrobin
server static 127.0.0.1:4331 check
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
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我们在配置文件的最后面，将默认的端口从4331修改成80
然后添加服务器
更改前
更改后
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global
log 127.0.0.1 local2
chroot /var/lib/haproxy
pidfile /var/run/haproxy.pid
maxconn 4000
user haproxy
group haproxy
daemon
stats socket /var/lib/haproxy/stats
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
frontend main *:80
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
backend static
balance roundrobin
server static 127.0.0.1:80 check
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
server app5 192.168.5.21:80 check
server app6 192.168.5.22:80 check
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然后启动haproxy服务
然后测试访问haproxy访问
我们通过本地查看端口监听状态
我们发现默认的端口是5000
我们使用5000端口在访问一下
接下来我们更改默认端口
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vim /etc/haproxy/haproxy.cfg
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修改为80
修改后我们重启
我们查看端口监听状态
测试访问
本文转自 高文龙 51CTO博客，原文链接：http://blog.51cto.com/gaowenlong/1883159，如需转载请自行联系原作者
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