ngx upstream round robin bug?

[Maxim Dounin]

Hello!

On Fri, Dec 23, 2011 at 04:41:59AM -0500, defage wrote:

> I use nginx as a load balancing for backend web server.
>  if this upstream has n servers, and when the number of backend web
> server can't connect(502 or down) be equal n-1, nginx will response  502
> or 503 status to client.  
> I did some test, only in the use of directer like:
>     server 10.10.1.2:7003 max_fails=NUM1 fail_timeout=NUM2;
> 
> within NUM2 second time, send request times > NUM1, the (NUM1+1)st 
> resquest will response 502 or 503. The above will be happened.
> 
> nginx version:1.0.11, centos5.4 x86_64
> this is my conf
> upstream backend {
>     server 10.10.1.2:7003 max_fails=10 fail_timeout=100;  #normal
> service
>     server 10.10.1.3:7004 max_fails=10 fail_timeout=100;  #had down
>     server 10.10.1.4:7005 max_fails=10 fail_timeout=100;  #had down
> }
> 
> location / {
>     proxy_pass        http://backend;
> }
> 
> the access_log when error happened like:
> 1324630768.256 cas.sdo.com
> /cas/login?gateway=true&service=http://newkoo.com 502 10.10.1.4:7005,
> backend 125.64.219.39, 10.129.1.230 0.002, 0.000

Looks like this one:
http://trac.nginx.org/nginx/ticket/64

Maxim Dounin