diff --git a/manifests/backend/bind9.pp b/manifests/backend/bind9.pp
index 9b9e7d3b..63a474ff 100644
--- a/manifests/backend/bind9.pp
+++ b/manifests/backend/bind9.pp
@@ -65,10 +65,10 @@ class designate::backend::bind9 (
   $rndc_controls                    = undef,
   $rndc_port                        = 953,
   Hash[Integer, String] $ns_records = {1 => 'ns1.example.org.'},
-  Array[String[1]] $nameservers     = ['127.0.0.1'],
-  Array[String[1]] $bind9_hosts     = ['127.0.0.1'],
+  Array[String[1], 1] $nameservers  = ['127.0.0.1'],
+  Array[String[1], 1] $bind9_hosts  = ['127.0.0.1'],
   $dns_port                         = 53,
-  Array[String[1]] $mdns_hosts      = ['127.0.0.1'],
+  Array[String[1], 1] $mdns_hosts   = ['127.0.0.1'],
   $mdns_port                        = 5354,
   Array[String[1]] $also_notifies   = [],
   Boolean $configure_bind           = true,
diff --git a/manifests/backend/pdns4.pp b/manifests/backend/pdns4.pp
index 55690144..4a789eac 100644
--- a/manifests/backend/pdns4.pp
+++ b/manifests/backend/pdns4.pp
@@ -43,9 +43,9 @@
 #
 class designate::backend::pdns4 (
   String[1] $api_token,
-  Array[String[1]] $pdns4_hosts     = ['127.0.0.1'],
+  Array[String[1], 1] $pdns4_hosts  = ['127.0.0.1'],
   $pdns4_port                       = 53,
-  Array[String[1]] $mdns_hosts      = ['127.0.0.1'],
+  Array[String[1], 1] $mdns_hosts   = ['127.0.0.1'],
   $mdns_port                        = 5354,
   String[1] $api_endpoint           = 'http://127.0.0.1:8081',
   Optional[String[1]] $tsigkey_name = undef,