Example, working, NGINX config for proxying to Unifi Controller software and using letsencrypt. Includes websocket fix.

nginx-unificontroller.conf

# I had a bit of trouble getting my unifi controller (hosted offsite) to use a proxy/letsencrypt. So here are the fruits of my labor. 
# The unifi default port is 8443 running on localhost. 

# License: CC0 (Public Domain)

server {
        # SSL configuration
        #
        listen 443 ssl default_server;
        listen [::]:443 ssl default_server;

        server_name unifi.hostname.com;

        # Needed to allow the websockets to forward well.
        # Information adopted from here: https://community.ubnt.com/t5/EdgeMAX/Access-Edgemax-gui-via-nginx-reverse-proxy-websocket-problem/td-p/1544354
        location /wss/ {
                proxy_pass https://localhost:8443;
                proxy_http_version 1.1;
                proxy_buffering off;
                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection "Upgrade";
                proxy_read_timeout 86400;
        }

        location / {
                proxy_pass https://localhost:8443/; # The Unifi Controller Port
                proxy_set_header Host $host;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header X-Forward-For $proxy_add_x_forwarded_for;
        }

        # Unifi still internally uses its own cert. This was converted to PEM and
        # is trusted for the sake of this proxy. See here for details:
        # https://community.ubnt.com/t5/UniFi-Wireless/Lets-Encrypt-and-UniFi-controller/td-p/1406670
        ssl_trusted_certificate /etc/nginx/ssl/unifi/unifi-default-selfsign.pem;

        ssl_certificate /etc/letsencrypt/live/unifi.hostname.com/fullchain.pem; # managed by Certbot
        ssl_certificate_key /etc/letsencrypt/live/unifi.hostname.com/privkey.pem; # managed by Certbot
        include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
}

server {
        listen 80;
        listen [::]:80;

        server_name unifi.hostname.com;

        location / {
                return 301 https://$host$request_uri;
        }
}

I'm a noob working with Nginx.
My nginx is setup on docker - i can't seem to find how the " ssl_certificate" and "ssl_certificate_key" paths.
Can someone direct me towards where these values can be found and where above conf need to be added?

This is more an nginx and docker related question.
However, you still need basically the nginx-config for having ssl to be enabled

    ssl on;
    ssl_certificate /container-path/to/cert.pem;
    ssl_certificate_key /container-path/to/key.pem;

and then you need to e.g. bind-mount the certs/keys files from your host to your docker container.
Lets assume, they live on /host-path/to/cert.pem and /host-path/to/key.pem. If you use docker-compose, an except of the config might look like this

    volumes:
      - '/host-path/to/cert.pem:/container-path/to/cert.pem:ro'
      - '/host-path/to/key.pem:/container-path/to/key.pem:ro'

The ro tag is there to make the files read-only in the container.
Adjust for your usecase (bare-docker, k8, rancher, portainer etc accordingly).

I'm a noob working with Nginx.
My nginx is setup on docker - i can't seem to find how the " ssl_certificate" and "ssl_certificate_key" paths.
Can someone direct me towards where these values can be found and where above conf need to be added?

If you're using SWAG or a similar docker (nginx with auto letsencrypt/certbot), there's a chance you don't need to explicitly set ssl certs and/or ssl, just include the ssl.conf in this config.
Something like:
include /config/nginx/ssl.conf

Please take this with a huge grain of salt (a mountain of it) as I'm a total noob who's just looking around at how to proxy non http(s) traffic to unifi controler so as to adopt a USG remotely and proxy all the ports/traffic through nginx as securely as possible. I HAVE MOSTLY NO CLUE WHAT I'M TALKING ABOUT!

and then you need to e.g. bind-mount the certs/keys files from your host to your docker container.
Lets assume, they live on /host-path/to/cert.pem and /host-path/to/key.pem. If you use docker-compose, an except of the config might look like this

    volumes:
      - '/host-path/to/cert.pem:/container-path/to/cert.pem:ro'
      - '/host-path/to/key.pem:/container-path/to/key.pem:ro'

Thanks for the reply. I'll give this a try.

I HAVE MOSTLY NO CLUE WHAT I'M TALKING ABOUT!

Welcome to the club :D

I took the original and added this line to the location /wss/ section and it seems to work.
proxy_set_header Origin '';

This also worked for me. The errors in the user interface disappeared. The return code in Nginx changed from 404 to 101 (Switching protocol).

This solved it also for me :) Thx!

Hi, I found myself wanting to do this for putting the Unifi controller inside an iFrame to use with HomeAssistant.

To add it into the iFrame you need to set a few additional headers into both the location /wss/ and location / parts of the nginx conf.

Here they are:

# Headers required for unifi to work
proxy_hide_header X-Frame-Options;
proxy_hide_header X-XSS-Protection;
proxy_hide_header X-Content-Type-Options;
proxy_cookie_path / "/; secure; SameSite=none";
add_header X-Frame-Options "ALLOWALL";

hi to all, i configure them, but open a white paga without any error.
location /wss/ {
proxy_pass https://192.168.1.5:8443;
proxy_http_version 1.1;
proxy_buffering off;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "Upgrade";
proxy_read_timeout 86400;
}
location / {
proxy_pass https://192.168.1.5:8443;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forward-For $proxy_add_x_forwarded_for;
proxy_set_header Upgrade $http_upgrade;
proxy_http_version 1.1;
proxy_set_header Connection "upgrade";

}