Katello 3.15 upgrade failure with "python3-django-admin migrate --noinput"

I’m presuming just as root with no special environment:

# python3-django-admin migrate --noinput
Traceback (most recent call last):
  File "/bin/python3-django-admin", line 11, in <module>
    load_entry_point('Django==2.2.10', 'console_scripts', 'django-admin')()
  File "/usr/lib/python3.6/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/usr/lib/python3.6/site-packages/django/core/management/__init__.py", line 375, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/lib/python3.6/site-packages/django/core/management/base.py", line 323, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/lib/python3.6/site-packages/django/core/management/base.py", line 361, in execute
    self.check()
  File "/usr/lib/python3.6/site-packages/django/core/management/base.py", line 390, in check
    include_deployment_checks=include_deployment_checks,
  File "/usr/lib/python3.6/site-packages/django/core/management/commands/migrate.py", line 64, in _run_checks
    issues = run_checks(tags=[Tags.database])
  File "/usr/lib/python3.6/site-packages/django/core/checks/registry.py", line 72, in run_checks
    new_errors = check(app_configs=app_configs)
  File "/usr/lib/python3.6/site-packages/django/core/checks/database.py", line 9, in check_database_backends
    for conn in connections.all():
  File "/usr/lib/python3.6/site-packages/django/db/utils.py", line 216, in all
    return [self[alias] for alias in self]
  File "/usr/lib/python3.6/site-packages/django/db/utils.py", line 213, in __iter__
    return iter(self.databases)
  File "/usr/lib/python3.6/site-packages/django/utils/functional.py", line 80, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/usr/lib/python3.6/site-packages/django/db/utils.py", line 147, in databases
    self._databases = settings.DATABASES
  File "/usr/lib/python3.6/site-packages/django/conf/__init__.py", line 79, in __getattr__
    self._setup(name)
  File "/usr/lib/python3.6/site-packages/django/conf/__init__.py", line 64, in _setup
    % (desc, ENVIRONMENT_VARIABLE))
django.core.exceptions.ImproperlyConfigured: Requested setting DATABASES, but settings are not configured. You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings.