I have a single server, running a single tomcat instance. I have set it up like this:

upstream tomcat { server 127.0.0.1:8180; }

server { listen 80; server_name webmail.example.org *.webmail.example.org;

access_log /var/log/nginx/webmail-access_log; error_log /var/log/nginx/webmail-error_log info;

location / { root /srv/www/example.org; index index.jsp index.php index.html index.htm; rewrite ^ /intouch/ redirect; }

location /intouch { proxy_pass http://tomcat/intouch; include /etc/nginx/proxy.conf; }

error_page 500 502 503 504 /50x.html; location = /50x.html { root /var/www/nginx-default; }

}

Now I know that upstream should be used for load balancing, but does it make a difference if I use tomcat only with proxy_pass or if I use it with upstream and proxy_pass?

Can anyone tell me the difference, besides load balancing idea?