Django runserver on Docker does not respond when opened in the browser

Question

I am just a beginner at this

So when I run

sudo docker-compose run web python manage.py runserver    

it shows

Starting thirddj_db_1 ... done  
usr/local/lib/python3.6/site-packages/psycopg2/__init__.py:144: 
UserWarning: The psycopg2 wheel package will be renamed from release 
2.8; in order to keep installing from binary please use "pip install 
psycopg2-binary" instead. For details see: 
<http://initd.org/psycopg/docs/install.html#binary-install-from-pypi>.
""")
/usr/local/lib/python3.6/site-packages/psycopg2/__init__.py:144: 
UserWarning: The psycopg2 wheel package will be renamed from release 
2.8; in order to keep installing from binary please use "pip install 
psycopg2-binary" instead. For details see: 
<http://initd.org/psycopg/docs/install.html#binary-install-from-pypi>.
""")
Performing system checks...

System check identified no issues (0 silenced).
April 11, 2018 - 19:15:59
Django version 1.11.12, using settings 'composeexample.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C.

And then when I opened it in my browser, it shows the site cant be reached

But when i run

docker-compose up

it shows

web_1  | /usr/local/lib/python3.6/site- 
packages/psycopg2/__init__.py:144: UserWarning: The psycopg2 wheel 
package will be renamed from release 2.8; in order to keep installing 
from binary please use "pip install psycopg2-binary" instead. For 
details see: <http://initd.org/psycopg/docs/install.html#binary- 
install-from-pypi>.
web_1  |   """)
web_1  | /usr/local/lib/python3.6/site- 
packages/psycopg2/__init__.py:144: UserWarning: The psycopg2 wheel 
package will be renamed from release 2.8; in order to keep installing 
from binary please use "pip install psycopg2-binary" instead. For 
details see: <http://initd.org/psycopg/docs/install.html#binary- 
install-from-pypi>.
web_1  |   """)
web_1  | Performing system checks...
web_1  | 
web_1  | System check identified no issues (0 silenced).
web_1  | April 11, 2018 - 19:21:41
web_1  | Django version 1.11.12, using settings   
'composeexample.settings'
web_1  | Starting development server at http://0.0.0.0:8000/
web_1  | Quit the server with CONTROL-C.

And then when I opened it in my browser, it works

so i want to know Why sudo docker-compose run web python manage.py runserver is not working and what is the difference between both commands.

and here is my docker-compose file

version: '3'

services:
  db:
    image: postgres
  web:
    build: .
    command: python3 manage.py runserver 0.0.0.0:8000
    volumes:
      - .:/code
    ports:
      - "8000:8000"
    depends_on:
      - db

Answer 1

When you run the web container it's necessary run command with the service's ports enabled and mapped to the host.

Try this:

sudo docker-compose run --service-ports web python manage.py runserver