diff --git a/lib/puppet/provider/mistral.rb b/lib/puppet/provider/mistral.rb
index 3480c24..5b8fe9e 100644
--- a/lib/puppet/provider/mistral.rb
+++ b/lib/puppet/provider/mistral.rb
@@ -16,6 +16,7 @@ class Puppet::Provider::Mistral < Puppet::Provider::MistralWorkflowRequester
   end
 
   def self.mistral_request(service, action, error, properties=nil)
+    warning('Usage of keystone_authtoken parameters is deprecated.')
     properties ||= []
     @credentials.username = mistral_credentials['username']
     @credentials.password = mistral_credentials['password']
diff --git a/releasenotes/notes/provider-deprecate-at-params-484966d315226d95.yaml b/releasenotes/notes/provider-deprecate-at-params-484966d315226d95.yaml
new file mode 100644
index 0000000..ab0a84b
--- /dev/null
+++ b/releasenotes/notes/provider-deprecate-at-params-484966d315226d95.yaml
@@ -0,0 +1,9 @@
+---
+deprecations:
+  - |
+    The ``mistral_workflow`` resource type has been using the credential
+    written in the ``[keystone_authtoken]`` section of ``mistral.conf``.
+    However this behavior has been deprecated and now the resource types first
+    looks for the yaml files in ``/etc/openstack/puppet``. Make sure one of
+    ``clouds.yaml`` or ``admin-clouds.yaml`` (which is created by
+    puppet-keystone) is created in that directory.