Memcache processing requests leads to ctlplane issues and horizon down

Issue

• memcache has issues and leads to ctlplane commands not work and horizon login failing etc

2021-06-08 11:22:38,836 34 ERROR django.request Internal Server Error: /dashboard/auth/login/
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/django/core/handlers/exception.py", line 35, in inner
    response = get_response(request)
  File "/usr/lib/python3.6/site-packages/django/core/handlers/base.py", line 128, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/usr/lib/python3.6/site-packages/django/core/handlers/base.py", line 126, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/usr/lib/python3.6/site-packages/django/views/decorators/debug.py", line 76, in sensitive_post_parameters_wrapper
    return view(request, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/utils/decorators.py", line 142, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/views/decorators/cache.py", line 44, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/openstack_auth/views.py", line 123, in login
    redirect_authenticated_user=False)(request)
  File "/usr/lib/python3.6/site-packages/django/views/generic/base.py", line 69, in view
    return self.dispatch(request, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/utils/decorators.py", line 62, in _wrapper
    return bound_func(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/views/decorators/debug.py", line 76, in sensitive_post_parameters_wrapper
    return view(request, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/utils/decorators.py", line 58, in bound_func
    return func.__get__(self, type(self))(*args2, **kwargs2)
  File "/usr/lib/python3.6/site-packages/django/utils/decorators.py", line 62, in _wrapper
    return bound_func(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/utils/decorators.py", line 142, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/utils/decorators.py", line 58, in bound_func
    return func.__get__(self, type(self))(*args2, **kwargs2)
  File "/usr/lib/python3.6/site-packages/django/utils/decorators.py", line 62, in _wrapper
    return bound_func(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/views/decorators/cache.py", line 44, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/utils/decorators.py", line 58, in bound_func
    return func.__get__(self, type(self))(*args2, **kwargs2)
  File "/usr/lib/python3.6/site-packages/django/contrib/auth/views.py", line 66, in dispatch
    return super().dispatch(request, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/views/generic/base.py", line 89, in dispatch
    return handler(request, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/views/generic/edit.py", line 142, in post
    return self.form_valid(form)
  File "/usr/lib/python3.6/site-packages/django/contrib/auth/views.py", line 95, in form_valid
    auth_login(self.request, form.get_user())
  File "/usr/lib/python3.6/site-packages/django/contrib/auth/__init__.py", line 140, in login
    request.session.cycle_key()
  File "/usr/lib/python3.6/site-packages/django/contrib/sessions/backends/base.py", line 300, in cycle_key
    self.create()
  File "/usr/lib/python3.6/site-packages/django/contrib/sessions/backends/cache.py", line 51, in create
    "Unable to create a new session key. "
RuntimeError: Unable to create a new session key. It is likely that the cache is unavailable.