I have an independent Docker container just for nginx with “host” network mode, which should be able to directly communicate with any other containers running on the local machine.

I have a separate Docker container with an http service that is exposed on the same host via port 4500, and I just want to be able to access it from my local network with a simple redirect, i.e. instead of curl http://192.168.1.8:4500 i want to do curl http://192.168.1.8/service.

Below is my nginx.conf:

events {}

http {
    server {
        listen 80;

        location /service/ {
          proxy_pass http://localhost:4500/;
        }
    }
}

and docker-compose.yaml:

services:
  nginx:
    build: .
    container_name: nginx
    network_mode:
        "host"
    volumes:
      - ./nginx/conf.d:/etc/nginx/conf.d

And my Dockerfile:

FROM nginx:latest
COPY nginx.conf /etc/nginx/conf.d/default.conf

However, when I attempt to access http://192.168.1.8/service I’m seeing this logged error when attempting to access http://localhost/service, and a 502 Bad Gateway client-side:

[error] 22#22: *1 connect() failed (111: Connection refused) 
while connecting to upstream,
client: 192.168.1.8,
server: ,
request: "GET /service/ HTTP/1.1",
upstream: "http://192.168.1.8:50000/admin/",
host: "desktop.com"

I have no idea why it’s using port 50000, it should be using port 4500 as I have in the nginx.conf. The upstream IP is correct, however.