Load Balancing - Web Applications with NGINX - ruby-on-rails

Question

I have a web application ruby on rails who is not configured to multithreading.
In nginx config, I set up an upstream block to be load balanced.
Like this :
upstream myapp {
server 127.0.0.1:3075;
server 127.0.0.1:3076;
server 127.0.0.1:3077;
}
I set up also 3 process thin with 3 ports (3075,3076,3077).
I think when my first application '127.0.0.1:3075' is busy, all the request will be balanced automatically to my second application '127.0.0.1:3076' or the third one.
But load balancing is not work, even though my three web applications are running correctly independent.
Please help me to find errors.
------------------- nginx config --------------------
upstream myapp_hosts {
server 127.0.0.1:3075;
server 127.0.0.1:3076;
server 127.0.0.1:3077;
}
server {
listen 80;
server_name myapp.mydomain.com;
rewrite ^(.*)$ https://myapp.mydomain.com$1 permanent; # rewrite for https, i have another bloc server listen 443.
access_log /var/log/nginx/myapp.access.log;
location / {
proxy_pass http://myapp_hosts/;
proxy_connect_timeout 900;
proxy_send_timeout 900;
proxy_read_timeout 900;
proxy_buffer_size 16k;
proxy_buffers 32 16k;
proxy_busy_buffers_size 64k;
}
location /public {
root /var/www/nemo/;
}
location /images {
root /var/www/nemo/assets/;
}
location /javascripts {
root /var/www/nemo/assets/;
}
location /stylesheets {
root /var/www/nemo/assets/;
}
client_max_body_size 10m;
client_body_buffer_size 128k;
client_header_buffer_size 64k;
}

Answer 1

What is the purpose of your rewrite?
rewrite ^(.*)$ http://myapp.mydomain.com$1 permanent;
It looks like it's going to constantly redirect anything to itself based off of those rules, resulting in a redirect loop. You may have mixed this line up with an HTTPS redirect configuration you found somewhere else, perhaps?
Try removing that line and see if it works.