diff --git a/lib/puppet/provider/openstack/credentials.rb b/lib/puppet/provider/openstack/credentials.rb
index afade9c2..1fa852a1 100644
--- a/lib/puppet/provider/openstack/credentials.rb
+++ b/lib/puppet/provider/openstack/credentials.rb
@@ -45,10 +45,10 @@ class Puppet::Provider::Openstack::Credentials
   end
 
   def unset
-    KEYS.each do |key|
-      if key != :identity_api_version &&
-        self.instance_variable_defined?("@#{key}")
-        set(key, '')
+    self.instance_variables.each do |var|
+      if var.to_s != '@identity_api_version' &&
+        self.instance_variable_defined?(var.to_s)
+        set(var.to_s.sub(/^@/,''), '')
       end
     end
   end
diff --git a/spec/unit/provider/openstack/credentials_spec.rb b/spec/unit/provider/openstack/credentials_spec.rb
index 1562454f..3baa4eb4 100644
--- a/spec/unit/provider/openstack/credentials_spec.rb
+++ b/spec/unit/provider/openstack/credentials_spec.rb
@@ -86,6 +86,7 @@ describe Puppet::Provider::Openstack::Credentials do
         creds.auth_url = 'auth_url'
         creds.password = 'password'
         creds.project_name = 'project_name'
+        creds.domain_name = 'domain_name'
         creds.username = 'username'
         creds.token = 'token'
         creds.endpoint = 'endpoint'
@@ -94,6 +95,7 @@ describe Puppet::Provider::Openstack::Credentials do
         expect(creds.auth_url).to eq('')
         expect(creds.password).to eq('')
         expect(creds.project_name).to eq('')
+        expect(creds.domain_name).to eq('')
         expect(creds.username).to eq('')
         expect(creds.token).to eq('')
         expect(creds.endpoint).to eq('')