Where is the error in docker run command?

Question

Docker

Good afternoon!
There is a docker-compose.yml file, which I run docker-compose up and everything works without problems, but for some reason I can’t run the same instructions through docker run.
docker-compose.yml

version: '3'

services:
  weba:
    image:docker-nginx-proxy-example_weba
    expose:
      - 8081
    environment:
      - VIRTUAL_HOST=a.localhost

So I try to run through docker run, it does not happen properly because nginx does not give the page to a.localhost

sudo docker run --expose=8081 -e VIRTUAL_HOST=a.localhost docker-nginx-proxy-example_weba

Where am I making a mistake?

Answer 1

expose does not forward ports to the host, so it's interesting which nginx you are knocking on :)
And the main significant difference: docker-compose also creates a default docker network in which it raises containers.