No Response on NGINX when using upstream - nginx

Question

I'm trying to load balance a web application through nginx, It works fine for all will my web application calls a service with sub-path.
for example it works
http://example.com/luna/
but not for
http://example.com/luna/sales
My nginx.conf
user nobody;
worker_processes auto;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
map $http_upgrade $connection_upgrade {
default upgrade;
'' close;
}
upstream lunaups {
server myhostserver1.com:8080;
server myhostserver2.com:8080;
}
server {
listen 80;
server_name example.com;
proxy_pass_header Server;
location = / {
rewrite ^ http://example.com/luna redirect;
}
location /luna {
rewrite ^$/luna/(.*)/^ /$1 redirect;
proxy_pass http://lunaups;
#add_header X-Upstream $upstream_addr;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
}
my web application calls a service with additional subpath like /luna/sales fails to return response. What am i missing here?
It works if i remove one of my host server from upstream, But when I add second host on upstream it fails to return response.
Is my rewrite rule wrong or my configurations as whole is wrong?

Answer 1

There are four suffixes to the rewrite directive and they all have specific uses. See this document for details.
If you want the URI / to be mapped to /luna without changing the URL in the browser, you would use an internal rewrite with rewrite ... last. For example:
location = / {
rewrite ^ /luna last;
}
In the location /luna block, you need to rewrite the URI before sending it to proxy_pass statement (without leaving the location block), which requires a rewrite ... break. For example:
location /luna {
rewrite ^/luna(/.*)$ $1 break;
rewrite ^ / break;
proxy_pass http://lunaups;
}
The first rewrite changes any URI with a sub-path, and the second rewrite handles the URI without a sub-path.
See this useful resource on regular expressions.