问Centos7.2 部署django路由问题？

Centos7.2 部署django为啥只出现Django欢迎页面，修改了urls为啥没有效果，只能访问admin

"""

from django.conf.urls import url

from django.contrib import admin

from main.views import host

urlpatterns = [

url(r'^host/$', host),

]

Page not found (404)

Request Method: GET

Request URL: http://193.112.2.120/f

Using the URLconf defined in mysite.urls, Django tried these URL patterns, in this order:

^admin/

The current path, f, didn't match any of these.

You're seeing this error because you have DEBUG = True in your Django settings file. Change that to False, and Django will display a standard 404 page.