# urls.py
path('admin/', include('site.apps.admin.urls'))

# admin apps.py
class AdminConfig(AppConfig):
    name = 'site.apps.admin'
    label = 'my.admin'

# admin __init__.py
default_app_config = 'site.apps.admin.apps.AdminConfig'

# hosts.py
host_patterns = patterns('',
    host(r'www', settings.ROOT_URLCONF, name='www'),  # <-- The `name` we used to in the `DEFAULT_HOST` setting
    host(r'admin', 'admin.urls', name='admin'),
)

# setting.py
INSTALLED_APPS = [
    'django_hosts',
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'site.apps.core',
    'site.apps.admin',
]

MIDDLEWARE = [
    'django_hosts.middleware.HostsRequestMiddleware',
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'site.urls'
ROOT_HOSTCONF = 'site.hosts'
DEFAULT_HOST = 'www'