Condition in upstream

[thigomes]

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.

Att,
Thiago Gomes

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,230678,230680#msg-230680