nignx搭建负载均衡

在http里面设置upstream组，其中包含三个服务器。在server的location块中的proxy_pass指令告诉Nginx将请求转发到这个组。

http {
  upstream myapp {
    server app1.example.com;
    server app2.example.com;
    server app3.example.com;
  }

  server {
    listen 80;
    server_name myapp.example.com;

    location / {
      proxy_pass http://myapp;
    }
  }
}

Nginx默认使用轮询算法来平均分配组中所有服务器的流量。
要调整流量的权重分配，可以在nginx配置文件的服务器块中使用“weight”参数。权重参数为每个服务器分配一个权重，权重较高的服务器将获得更大比例的流量.

upstream backend {
    server backend1.example.com weight=3;
    server backend2.example.com weight=1;
    server backend3.example.com weight=2;
}

在此示例中，backend1将收到比backend2多三倍的流量，backend3将收到比backend2多两倍的流量。
如果您想要添加备用机，可以在upstream块中添加多个server行，如下所示：

upstream backend {
    server backend1.example.com weight=3;
    server backend2.example.com weight=1;
    server backend3.example.com weight=2;
    server backup1.example.com backup;
    server backup2.example.com backup;
}

在此示例中，backup1和backup2是备用服务器，只有在所有其他服务器都不可用时才会接收流量。backup关键字指示Nginx将其视为备用服务器。

http {
    upstream backend {
        server backend1.example.com weight=3;
        server backend2.example.com weight=1;
        server backend3.example.com weight=2;
        server backup1.example.com backup;
        server backup2.example.com backup;
    }

    server {
        listen 80;
        server_name example.com;

        location / {
            proxy_pass http://backend;
            proxy_set_header Host $host;
           #真实用户IP
            proxy_set_header X-Real-IP $remote_addr; 
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

            # 健康检查
            proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
            proxy_connect_timeout 2s;
            proxy_read_timeout 10s;
            proxy_send_timeout 10s;
            proxy_http_version 1.1;
            proxy_set_header Connection "";
        }

        # 会话保持
        upstream ip_hash {
            ip_hash;
            server backend1.example.com;
            server backend2.example.com;
            server backend3.example.com;
        }

        # SSL / TLS
        listen 443 ssl;
        ssl_certificate /path/to/cert.pem;
        ssl_certificate_key /path/to/key.pem;

        # 安全性
        location /admin/ {
            allow 192.168.1.0/24;
            deny all;
            proxy_pass http://backend;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        }

        # 性能
        worker_processes auto;
        worker_cpu_affinity auto;
        worker_rlimit_nofile 100000;
        worker_connections 1024;
        keepalive_timeout 65;
        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        types_hash_max_size 2048;
        server_tokens off;
        client_max_body_size 100m;
        gzip on;
        gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;
    }
}