0. 下载并安装

至 HAProxy 官网，最新稳定版本

$ wget http://www.haproxy.org/download/1.8/src/haproxy-1.8.9.tar.gz
$ tar -zxvf haproxy-1.8.9.tar.gz
$ make TARGET=linux2628 ARCH=x86_64 PREFIX=/usr/local/haproxy
$ sudo make install PREFIX=/usr/local/haproxy

参数说明

TARGET: 使用 uname -r 查看内核

linux22 for Linux 2.2
linux24 for Linux 2.4 and above (default)
linux24e for Linux 2.4 with support for a working epoll (> 0.21)
linux26 for Linux 2.6 and above
linux2628 for Linux 2.6.28, 3.x, and above (enables splice and proxy)

$ uname -r
3.10.0-693.5.2.el7.x86_64

ARCH: ARCH=x86_64，系统位数

PREFIX: PREFIX=/usr/local/haprpxy，haprpxy安装路径

1. 基本配置

$ sudo mkdir -p /etc/haproxy
$ sudo touch /etc/haproxy/haproxy.cfg

global                                          # 全局属性
    daemon                                      # 以daemon方式在后台运行
    maxconn 256                                 # 最大同时256连接
    pidfile /usr/local/haproxy/conf/haproxy.pid # 指定保存HAProxy进程号的文件

defaults                                        # 默认参数
    mode http                                   # http模式
    timeout connect 5000ms                      # 连接server端超时5s
    timeout client 50000ms                      # 客户端响应超时50s
    timeout server 50000ms                      # server端响应超时50s

frontend http-in                                # 前端服务http-in
    bind *:8080                                 # 监听8080端口
    default_backend nginx-server                # 请求转发至名为nginx-server的后端服务

backend nginx-server                            # 后端服务
    server server1 127.0.0.1:80 maxconn 32      # nginx 80 端口服务，HAProxy同时最多向这个服务发起32个连接

2. 测试

$ /usr/local/haproxy/sbin/haproxy -f /etc/haproxy/haproxy.cfg
$ sudo systemctl start nginx
$ curl http://127.0.0.1:8080/

<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

3. more

添加统计页面

...

listen haproxy_stats                            # haproxy 统计页面
    bind *:8081
    mode http
    stats refresh 3s                            # 页面刷新间隔
    stats uri /haproxy-stats                    # uri
    stats auth admin:admin                      # 授权账户