Nginxでクエリストリングを見て振り分け先を切り替える。 http://localhost/test.txt?para1=AAA ならバランサ1、 http://localhost/test.txt?para1=CCC ならバランサ2

nginx.conf

user              nginx;
worker_processes  1;

error_log  /var/log/nginx/error.log;
pid        /var/run/nginx.pid;

events {
    worker_connections  1024;
}

http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';
    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    keepalive_timeout  65;

    ### バランサ定義
    upstream balancer01 {
      server 192.168.1.62;
      server 192.168.1.63;
    }
    upstream balancer02 {
      server 192.168.1.62;
    }
    upstream balancer03 {
      server 192.168.1.63;
    }

    ### パラメータみてバランサ切り替え
    map $arg_para1 $balancer {
        AAA balancer01;
        BBB balancer01;
        CCC balancer02;
        default balancer03;
    }

    ### server定義
    server {
        listen       80 default_server;
        server_name  _;
    
        location / {
          proxy_pass http://$balancer$request_uri;
        }
    }
}