Why does Docker open port 80 where it shouldn't?

Question

Docker

Good morning.
Actually, there is a project with two microservices: site and users. I need the site to be accessible on port 80, and for users all external ports would be closed. For this I use the following configuration:

Dockerfile\site

FROM php:7.2.19-apache

# тут просто устанавливаю все, НИКАКИХ директив, только RUN

EXPOSE 80

dockerfile\users

FROM php:7.2.19-apache

# тут просто устанавливаю все, НИКАКИХ директив, только RUN

docker-compose.yml

version: '3'
services: 
  site:
    build: './site'
    ports: 
      - 80:80
    links:
      - "users"
  users:
    build: './users'
    expose:
      - 8000

However, the problem is that when I run `docker-compose up --build' it throws the error "Error starting userland proxy: listen tcp 0.0.0.0:80: bind: Only one usage of each socket address (protocol/network address/port) is normally permitted". At the same time, `docker ps` shows that the service `users` (!!!) is running and listening on port 80, but why? This port is clearly mapped on the site service!
Where did I go wrong? make Docker:
- bind port 80 from my machine to the container port (80:80)
- leave users alone so that this service can only be accessed from inside the site container on port 8000

Answer 1

No one is already sitting on port 80 on your host machine?