Following the Get Started: Stack server stuck loading page endlessly

Question

I've been following the docker get started guide quite closely - except for a few changes in my python app, which I have confirmed are working without issue from the version I have pushed to docker hub.

However, when I get to Part 3 and attempt to load up localhost:80, the page simply loads endlessly.

My commands:

$ docker swarm init
Swarm initiated: ...
$ docker stack deploy -c docker-compose.yml
Creating network getstartedlab_webnet
Creating service getstartedlab_web
$ docker stack ps getstartedlab
ID                  NAME                  IMAGE                     NODE                DESIRED STATE       CURRENT STATE            ERROR               PORTS
fhxqr2u8hxar        getstartedlab_web.1   mctague/friendlyhello:2   cube                Running             Running 29 seconds ago                       
4t9mu9r8147e        getstartedlab_web.2   mctague/friendlyhello:2   cube                Running             Running 28 seconds ago                       
duute2pvgu9z        getstartedlab_web.3   mctague/friendlyhello:2   cube                Running             Running 30 seconds ago                       
9kav6v27qfjn        getstartedlab_web.4   mctague/friendlyhello:2   cube                Running             Running 29 seconds ago                       
1s2imbiuk6e2        getstartedlab_web.5   mctague/friendlyhello:2   cube                Running             Running 29 seconds ago                       
$ docker logs <one of the running containers>
 * Running on http://0.0.0.0:80/ (Press CTRL+C to quit)
$ curl localhost:80
< either an endless loading that I have to cancel with ^C,
  *OR* Connection refused >

---

docker-compose.yml

version: "3"
services:
  web:
    image: mctague/friendlyhello:2
    deploy:
      replicas: 5
      resources:
        limits:
          cpus: "0.1"
          memory: 50M
      restart_policy:
        condition: on-failure
    ports:
      - "80:80"
    networks:
      - webnet
networks:
  webnet:

Answer 1

In some systems, curl connects to ip6 by default for localhost. So you can run curl using:

$ curl 127.0.0.1:80

or

$ curl -4 localhost:80