I have deployed OpenStack using kolla-ansible. I got the following error when access horizon web frontend:

mod_wsgi (pid=65): Exception occurred processing WSGI script '/usr/share/openstack-dashboard/openstack_dashboard/wsgi/django.wsgi'.
Traceback (most recent call last):
  File "/usr/share/openstack-dashboard/openstack_dashboard/wsgi/django.wsgi", line 40, in <module>
    application = get_wsgi_application()
  File "/usr/lib/python2.7/site-packages/django/core/wsgi.py", line 13, in get_wsgi_application
    django.setup(set_prefix=False)
  File "/usr/lib/python2.7/site-packages/django/__init__.py", line 22, in setup
    configure_logging(settings.LOGGING_CONFIG, settings.LOGGING)
  File "/usr/lib/python2.7/site-packages/django/conf/__init__.py", line 56, in __getattr__
    self._setup(name)
  File "/usr/lib/python2.7/site-packages/django/conf/__init__.py", line 41, in _setup
    self._wrapped = Settings(settings_module)
  File "/usr/lib/python2.7/site-packages/django/conf/__init__.py", line 110, in __init__
    mod = importlib.import_module(self.SETTINGS_MODULE)
  File "/usr/lib64/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/usr/share/openstack-dashboard/openstack_dashboard/settings.py", line 488, in <module>
    '.secret_key_store'))
  File "/usr/lib/python2.7/site-packages/horizon/utils/secret_key.py", line 69, in generate_or_read_from_file
    key = read_from_file(key_file)
  File "/usr/lib/python2.7/site-packages/horizon/utils/secret_key.py", line 51, in read_from_file
    with open(key_file, 'r') as f:
IOError: [Errno 13] Permission denied: '/tmp/.secret_key_store'

I have found the followinghttps://ask.openstack.org/en/question/30647/ioerror-errno-13-permission-denied-tmpsecret_key_store/ (solution), where I have chown horizon /tmp/.secret_key_store. However, I do not think this is the proper way for a kolla-ansible deployment.