Nginx not detecting the root location from config for Rails 3.2 app

[emclab]

Here is the error.log of nginx server running on ubuntu 12.04. 

    2014/03/17 12:47:17 [error] 7939#0: *1 open()
"/opt/nginx/html/mkl/authentify/signin" failed (2: No such file or
directory), client: xxx.xxx.228.66, server: xxx.xxx.109.181, request: "GET
/mkl/authentify/signin HTTP/1.1", host: "xxx.xxx.109.181"

In /opt/nginx/conf/nginx.conf, it is configured as following:

    server_name xxx.xxx.109.181;
    root /ebs/www/;
    passenger_enabled on;
    rails_env production;
    passenger_base_uri /mkl;

The root of nginx server is pointing to /ebs/www/. However the nginx is
accessing the /opt/nginx and throws out no such file error. What causes the
problem? Thanks.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,248743,248743#msg-248743