Simple configuration method for nginx load balancing

http  
    {  
      upstream www.test2.com {  
                server 10.1.165.36:80  weight = 3;          
        server 10.249.198.235;  
             server 10.1.168.1  down;   
             server 10.1.168.2  backup;  
            #ip_hash;  
       }  
      server  
      {  
            location / {  
                  proxy_pass        http://www.test2.com;  
                  proxy_set_header   Host             $host;  
                  proxy_set_header   X-Real-IP        $remote_addr;  
                  proxy_set_header  X-Forwarded-For  $proxy_add_x_forwarded_for;  
                  }  
    } 

Nginx load balancing requires adding upstream   and proxy_pass
in Server
server 10.1.165.36:80   weight = 3;   means that this server has 3 times the same probability of accessing
server 10.1.168.1   down;   does not use
for the time being server 10.1.168.2   backup;
is activated only when the pressure is high ip_hash; hash matching by IP address. However, there are some disadvantages. For example, if Nginx is not in the outermost layer, IP and
cannot be obtained proxy_pass http: / / www. test2. com