Proxy to all backends

[Igor Sysoev]

On Thu, Oct 01, 2009 at 09:02:18PM -0400, jkolen wrote:

> I have a rails app sitting behind nginx and every request is going to both of the mongrel instances. Pages are getting through. However, there are a few db intensive tasks that I don't want run two instances of. I've been playing with proxy_*_timeout and have turned proxy_next_upstream off and it still manages to duplicate each request.  No errors are reported. A single access is recorded for a page as well as a single logging of a destination. Pages are returning with status of 304 and load balancer is dutifully alternating between the two. (When I shut one down I get 502-Bad Gateway errors on alternate requests.) I've included by conf file. I'm running 0.5.33. Any ideas would be appreciated.

Do these db intensive tasks have specific URLs ?

> Thanks in advance,
> John
> 
> ---------------------------------------------------------------------------
> user www-data;
> worker_processes  2;
> 
> pid        /var/run/nginx.pid;
> 
> events {
>     worker_connections  1024;
> }
> 
> http {
>     include       /etc/nginx/mime.types;
>     default_type  application/octet-stream;
> 
>     sendfile        on;
>     tcp_nopush     on;
> 
>     keepalive_timeout  65;
>     tcp_nodelay        off;
> 
>     gzip  on;
> 
>     upstream myservers {
>       server 127.0.0.1:4010;
>       server 127.0.0.1:4011;
>     }
> 
>     server {
>       listen 80;
>       root /var/www/qpd/public;
> 
>       access_log  /var/log/nginx/access.log;
>       error_log   /var/log/nginx/error.log;
> 
>       rewrite_log on;
> 
>       location / {
>         proxy_set_header  X-Real-IP  $remote_addr;
>       	proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
>       	proxy_set_header Host $http_host;
>       	proxy_redirect false;
>     	client_max_body_size    10m;
> 	client_body_buffer_size 128k;
> 	proxy_connect_timeout   5;
> 	proxy_send_timeout      90;
> 	proxy_read_timeout      90;
> 	proxy_buffers           32 4k;
> 	proxy_next_upstream     off;
> 
>         log_format timing 
>            '$remote_addr - $remote_user [$time_local]  $request '
>            'upstream_response_time $upstream_response_time '
>            'msec $msec request_time $request_time  sent to $upstream_addr $upstream_status';
> 
> 	access_log  /var/log/nginx/proxy.log timing;
> 	if (-f $request_filename/index.html) {
> 	   rewrite (.*) $1/index.html break;
> 	}
> 	if (-f $request_filename.html) {
> 	   rewrite (.*) $1.html break;
> 	}
> 	if (!-f $request_filename) {
> 	   proxy_pass http://myservers;
> 	   break;
>         }
>      }
>    }
> }

You should replace these "if/rewrites" with simple "try_files":

    location / {
        try_files  $uri/index.html  $uri.thml  $uri  @mongrel;
    }

    location @mongrel {
        proxy_pass  ...
        ...
    }


-- 
Igor Sysoev
http://sysoev.ru/en/