负载均衡入门：HAProxy 双 Web 节点集群配置与验证

HAProxy安装

为了更好的快速掌握 HAProxy 的安装和使用，我们以一个案例来进行讲解。首先根据以下要求进行虚拟机的克隆。

1.1 搭建Web1

1、克隆一台虚拟机，初始化虚拟机（ip ，主机名，关闭防火墙，selinux）

[root@node1 ~]# hostnamectl set-hostname web1&&bash [root@web1 ~]# systemctl disable firewalld.service  Removed "/etc/systemd/system/multi-user.target.wants/firewalld.service". Removed "/etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service". [root@web1 ~]# setenforce 0 [root@web1 ~]# sed -i "s/SELINUX=enforcing/SELINUX=permissive/" /etc/selinux/config 

下载nginx

[root@web1 ~]# dnf install nginx -y Updating Subscription Management repositories. Unable to read consumer identity

This system is not registered with an entitlement server. You can use "rhc" or "subscription-manager" to register.

BaseOS                                                                                      2.7 MB/s | 2.7 kB     00:00     AppStream                                                                                   3.1 MB/s | 3.2 kB     00:00     Package nginx-2:1.20.1-22.el9.x86_64 is already installed. Dependencies resolved. Nothing to do. Complete!

修改欢迎页

[root@web1 ~]# echo "$(hostname) $(hostname -I)" > /usr/share/nginx/html/index.html

[root@web1 ~]# echo "health" > /usr/share/nginx/html/test.html

启动nginx并测试

[root@web1 ~]# systemctl start nginx [root@web1 ~]# curl localhost web1 192.168.72.10  [root@web1 ~]# curl 192.168.72.10  web1 192.168.72.10  [root@web1 ~]# 

1.2 搭建Web2

1、克隆一台虚拟机，初始化虚拟机（ip ，主机名，关闭防火墙，selinux）

[root@node1 ~]# hostnamectl set-hostname web2&&bash [root@web2 ~]# systemctl disable firewalld.service  Removed "/etc/systemd/system/multi-user.target.wants/firewalld.service". Removed "/etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service". [root@web2 ~]# setenforce 0 [root@web2 ~]# sed -i "s/SELINUX=enforcing/SELINUX=permissive/" /etc/selinux/config 

下载nginx

[root@web2 ~]# dnf install nginx -y Updating Subscription Management repositories. Unable to read consumer identity

This system is not registered with an entitlement server. You can use "rhc" or "subscription-manager" to register.

BaseOS                                                                                      2.7 MB/s | 2.7 kB     00:00     AppStream                                                                                   3.1 MB/s | 3.2 kB     00:00     Package nginx-2:1.20.1-22.el9.x86_64 is already installed. Dependencies resolved. Nothing to do. Complete! [root@web2 ~]#   

修改欢迎页，创建健康检测页面

[root@web2~]# echo "$(hostname) $(hostname -I)" > /usr/share/nginx/html/index.html

[root@web2 ~]# echo "health" > /usr/share/nginx/html/test.html

启动nginx并测试

[root@web2 ~]# systemctl start nginx [root@web2~]# curl localhost web1 192.168.72.20 [root@web2~]# curl 192.168.72.20 web1 192.168.72.20 [root@web2 ~]# 

1.3 搭建HAProxy

1、克隆一台虚拟机，初始化虚拟机（ip ，主机名，关闭防火墙，selinux）

[root@node1 ~]# hostnamectl set-hostname lb1&&bash [root@lb1 ~]# systemctl disable firewalld.service  Removed "/etc/systemd/system/multi-user.target.wants/firewalld.service". Removed "/etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service". [root@lb1 ~]# setenforce 0 [root@lb1 ~]# sed -i "s/SELINUX=enforcing/SELINUX=permissive/" /etc/selinux/config 

下载haproxy

[root@lb1 ~]# dnf install haproxy -y Updating Subscription Management repositories. Unable to read consumer identity

This system is not registered with an entitlement server. You can use "rhc" or "subscription-manager" to register.

BaseOS                                                                                      2.7 MB/s | 2.7 kB     00:00     AppStream                                                                                   3.1 MB/s | 3.2 kB     00:00     Dependencies resolved. ============================================================================================================================  Package                    Architecture              Version                            Repository                    Size ============================================================================================================================ Installing:  haproxy                    x86_64                    2.4.22-4.el9                       AppStream                    2.2 M

Transaction Summary ============================================================================================================================ Install  1 Package

Total size: 2.2 M Installed size: 6.6 M Downloading Packages: Running transaction check Transaction check succeeded. Running transaction test Transaction test succeeded. Running transaction   Preparing        :                                                                                                    1/1    Running scriptlet: haproxy-2.4.22-4.el9.x86_64                                                                        1/1    Installing       : haproxy-2.4.22-4.el9.x86_64                                                                        1/1    Running scriptlet: haproxy-2.4.22-4.el9.x86_64                                                                        1/1    Verifying        : haproxy-2.4.22-4.el9.x86_64                                                                        1/1  Installed products updated.

Installed:   haproxy-2.4.22-4.el9.x86_64                                                                                               

Complete!  

验证haproxy

[root@lb1 ~]# haproxy -v HAProxy version 2.4.22-f8e3218 2023/02/14 – https://haproxy.org/ Status: long-term supported branch – will stop receiving fixes around Q2 2026. Known bugs: http://www.haproxy.org/bugs/bugs-2.4.22.html Running on: Linux 5.14.0-570.12.1.el9_6.x86_64 #1 SMP PREEMPT_DYNAMIC Fri Apr 4 10:41:31 EDT 2025 x86_64

查看配置文件路径

[root@lb1 ~]# rpm -qc haproxy /etc/haproxy/haproxy.cfg                # 核心配置文件路径 /etc/logrotate.d/haproxy /etc/sysconfig/haproxy                # 启动选项所在文件

修改配置文件

[root@lb1 ~]# cp /etc/haproxy/haproxy.cfg{,.bak} [root@lb1 ~]# vim /etc/haproxy/haproxy.cfg [root@lb1 ~]# cat /etc/haproxy/haproxy.cfg #——————————————————————— # Example configuration for a possible web application.  See the # full configuration options online. # #   https://www.haproxy.org/download/1.8/doc/configuration.txt # #———————————————————————

#——————————————————————— # Global settings #——————————————————————— global     # to have these messages end up in /var/log/haproxy.log you will     # need to:     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

    ssl-default-bind-ciphers PROFILE=SYSTEM     ssl-default-server-ciphers PROFILE=SYSTEM

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     bind *:80     default_backend             webcluster

backend webcluster     balance     roundrobin     option httpchk GET /test.html     server      web1 192.168.72.10:80 check inter 2000 rise 2 fall 2 weight 2     server      web2 192.168.72.20:80 check inter 2000 rise 2 fall 2 weight 2 listen admin_status     bind *:9129     stats refresh 30s     stats uri /admin     stats auth admin:admin123     stats hide-version     stats admin if TRUE

启动haproxy

[root@lb1 ~]# systemctl start haproxy

[root@lb1 ~]# systemctl stop firewalld

打开浏览器访问

http://192.168.72.100:9129/admin

输出后，会弹出输入用户名和密码的窗口，我们输入在配置文件中配置的用户名（admin）和密码（admin123）后就可以登录成功。登录成功后就可以看到如下的界面了。