Condition in upstream

[Igor Sysoev]

On Sep 13, 2012, at 1:04 , thigomes wrote:

> Just to complete the information, in my case I have two configuration
> according with the web server, so:
> 
> # TO VARNISH
> location / {
>  proxy_redirect off; # Do not redirect this proxy - It needs to be
> pass-through
>  proxy_set_header Host $host;
>  proxy_set_header X-Real-IP $remote_addr;
>  proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
>  proxy_set_header X-Server-Address $server_addr;
>  proxy_connect_timeout   5s;
>  proxy_read_timeout      300s;
>  proxy_pass_header Set-Cookie;
>  proxy_pass http://localhost:6081; # Pass all traffic through to Varnish
> }
> 
> TO APACHE
> location / {
>  client_max_body_size    10m;
>  client_body_buffer_size 128k;
>  proxy_send_timeout   90;
>  proxy_read_timeout   90;
>  proxy_buffer_size    32k;
>  proxy_buffers     8 16k;
>  proxy_busy_buffers_size 64k;
>  proxy_temp_file_write_size 64k;
>  proxy_connect_timeout 30s;
>  proxy_redirect http://domain.com:8081 http://domain.com;
>  proxy_redirect http://www.domain.com:8081 http://www.domain.com;
> 
>  proxy_pass http://192.168.1.7:8081/;    
>  proxy_set_header   Host   $host;
>  proxy_set_header   X-Real-IP  $remote_addr;
>  proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
> }
> 
> In the case varnish server not response, the request  will forward to apache
> server.

Backup servers are not supported with ip_hash upstream.
You should use something like this:

upstream backend  {
      server 192.168.1.5:6081; # varnish server
      server 192.168.1.7:80 backup; # apache server
}

server {
    location / {
        proxy_pass  http://backend;
        ...
    }
}

However, you can omit varnish at all and use nginx built-in cache:

proxy_cache_path /data/nginx/cache levels=1:2 keys_zone=CACHE:10m;

server {
    location / {
        proxy_pass    http://192.168.1.7;
        proxy_cache   CACHE;
        ...
    }
}


--
Igor Sysoev
http://nginx.com/support.html