Nginx 负载均衡的实现

1. 机器准备

客户端	10.0.0.205
nginx	10.0.0.206
web1	10.0.0.203
web2	10.0.0.204

2. nginx 服务配置

# 下载 nginx

[root@ubuntu2204 ~]# apt install nginx -y

# 编辑配置文件，将请求分发到后端服务器 

[root@ubuntu2204 ~]# vim /etc/nginx/conf.d/load_balance.conf

upstream backend_servers {
    server 10.0.0.203:8081 weight=2; # 权重为 2
    server 10.0.0.204:8082 weight=1; # 权重为 1
}

server {
    listen 81;

    location / {
        proxy_pass http://backend_servers;
        proxy_set_header Host $host;
    }
}

# 检查配置

[root@ubuntu2204 ~]# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

# 重启 nginx 服务 

[root@ubuntu2204 ~]# systemctl restart nginx.service

3. 后端服务器准备

# 创建第一个后端服务
[root@ubuntu2204 ~]# mkdir -p /var/www/backend1
[root@ubuntu2204 ~]# echo "Backend Server 1" > /var/www/backend1/index.html
[root@ubuntu2204 ~]# python3 -m http.server 8081 --directory /var/www/backend1 &

# 创建第二个后端服务
[root@ubuntu2204 ~]# mkdir -p /var/www/backend2
[root@ubuntu2204 ~]# echo "Backend Server 2" > /var/www/backend2/index.html
[root@ubuntu2204 ~]# python3 -m http.server 8082 --directory /var/www/backend2 &

# 验证后端服务是否正常运行

[root@ubuntu2204 ~]# curl http://10.0.0.203:8081

Backend Server 1

[root@ubuntu2204 ~]# curl http://10.0.0.204:8082

Backend Server 2

4. 测试负载均衡

[root@ubuntu2204 ~]# for i in {1..10};do curl http://10.0.0.206:81;done
Backend Server 2
Backend Server 1
Backend Server 1
Backend Server 2
Backend Server 1
Backend Server 1
Backend Server 2
Backend Server 1
Backend Server 1
Backend Server 2

5. 健康检查

# 停止一个服务，测试nginx是否能检测到异常，并合理分发请求

[root@ubuntu2204 ~]# pkill -f "python3 -m http.server 8081"

# 客户端继续访问后端服务 

[root@ubuntu2204 ~]# for i in {1..10};do curl http://10.0.0.206:81;done
Backend Server 2
Backend Server 2
Backend Server 2
Backend Server 2
Backend Server 2
Backend Server 2
Backend Server 2
Backend Server 2
Backend Server 2
Backend Server 2