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upstream app_front_static {
    server 192.168.206.105:80;
}


Never seen it before, anyone knows, what it means?
    

        

    
            

                
    
    
        
    
    
        automatix14.6k31 gold badges118 silver badges245 bronze badges
        
    

            
    
        
            asked May 4, 2011 at 2:47
        
        
    
    
        
    
    
        gdbgdb7,81913 gold badges41 silver badges37 bronze badges
        
    

        
    





                
                
                    


                                        

            

            


    
    
It's used for proxying requests to other servers.

An example from http://wiki.nginx.org/LoadBalanceExample is:

http {
  upstream myproject {
    server 127.0.0.1:8000 weight=3;
    server 127.0.0.1:8001;
    server 127.0.0.1:8002;    
    server 127.0.0.1:8003;
  }

  server {
    listen 80;
    server_name www.domain.com;
    location / {
      proxy_pass http://myproject;
    }
  }
}


This means all requests for / go to the any of the servers listed under upstream XXX, with a preference for port 8000.
    
    
            
            
    
    
        
    
    
        Bahrom4,87234 silver badges44 bronze badges
        
    



            
    
        
            answered May 4, 2011 at 2:56
        
        
    
    
        
    
    
        Phil LelloPhil Lello8,6392 gold badges27 silver badges36 bronze badges
        
    

        
    





                

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If we have a single server we can directly include it in the proxy_pass directive. For example:
  server {
    ...
    location / {
      proxy_pass http://192.168.206.105:80;
      ...
    }
  }

But in case if we have many servers we use upstream to maintain the servers. Nginx will load-balance based on the incoming traffic, as shown in this answer.
    
    
            
            
    
    
        
    
    
        McLan2,6989 gold badges55 silver badges91 bronze badges
        
    



            
    
        
            answered Oct 14, 2020 at 13:32
        
        
    
    
        
    
    

        
    





                

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