Question

We are using nginx to front-end our apache connections with good results. I am now toying with the idea of also using nginx (a separate instance) to load balance some of the back-end services. In order to be able to do that I want to understand nginx proxy_next_upstream module behavior better.

syntax: proxy_next_upstream error | timeout | invalid_header | http_500 | http_502 | http_503 | http_504 | http_404 | off ...;

default:proxy_next_upstream error timeout;

context: http, server, location

Can I specifically use TCP RST as one of the parameters in there to mark down a load balanced server? What all does really 1st parameter i.e. “error” encapsulate? Can I add my errors (RSTs etc)? I have tried some ways of setting RSTs in there but that does not seem to work.

Answer 1

http://nginx.org/r/proxy_next_upstream

error — an error occurred while establishing a connection with the server, passing it a request, or reading the response header;

This must handle RST on SYN too.