CoreOS - Hosting cloud-config using nginx

Question

I've been using Hosting cloud-config using nginx as an example:

There's a config that you need to put into nginx config file:

location ~ ^/user_data {
  root /path/to/cloud/config/files;
  sub_filter $public_ipv4 '$remote_addr';
  sub_filter $private_ipv4 '$http_x_forwarded_for';
# sub_filter $private_ipv4 '$http_x_real_ip';
  sub_filter_once off;
  sub_filter_types '*';
}

However, when I do that, nginx -t gives:

nginx: [emerg] unknown "public_ipv4" variable
nginx: configuration file /etc/nginx/nginx.conf test failed

How do I fix this?

I'm using nginx 1.10.1 compiled with http_sub_module.

Answer 1

Right...so I really don't know who writes docs for CoreOS, but how can you make such a mistake, when the problem's been around for ages!

Basically, google 'nginx escape variable' and you'll get there. https://github.com/openresty/nginx-tutorials/blob/master/en/01-NginxVariables01.tut

Here's a copy if the site goes down:

geo $dollar {
    default "$";
}

server {
    listen 8080;

    location ~ ^/user_data {
        root /path/to/cloud/config/files;
        sub_filter ${dollar}public_ipv4 '$remote_addr';
        sub_filter ${dollar}private_ipv4 '$http_x_forwarded_for';
        # sub_filter ${dollar}private_ipv4 '$http_x_real_ip';
        sub_filter_once off;
        sub_filter_types '*';
    }

}