nginx实现两层代理转发

以下是nginx实现两层代理转发的示例配置：

http {
    upstream backend_servers {
        server 127.0.0.1:8000;
        server 127.0.0.1:8001;
    }

    server {
        listen 80;
        location / {
            proxy_pass http://backend_servers;
        }
    }
}

stream {
upstream stream_backend {
server 127.0.0.1:8000;
server 127.0.0.1:8001;
}

server {
listen 12345;
proxy_pass stream_backend;
}
}