how to make nginx loadbalancer give 404 when all upstream servers are down

[itpp2012]

karkunpavan Wrote:
-------------------------------------------------------
> <<client_IP>> - - [14/Aug/2015:13:43:45 +0000] "GET / HTTP/1.0" 502
> 172 "-" "ApacheBench/2.3"
> <<client_IP>> - - [14/Aug/2015:13:43:45 +0000] "GET / HTTP/1.0" 502
> 172 "-" "ApacheBench/2.3"
[...] 
> <<client_IP>> - - [14/Aug/2015:14:00:37 +0000] "GET / HTTP/1.1" 502
> 172 "-" "curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7
> NSS/3.13.1.0 zlib/1.2.3 libidn/1.18 libssh2/1.2.2"

I see a 502 for both tools, might be an 'ab' thing.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,260980,261000#msg-261000