diff --git a/manifests/config.pp b/manifests/config.pp
index 7e34d616b..8cc7a6440 100644
--- a/manifests/config.pp
+++ b/manifests/config.pp
@@ -22,6 +22,8 @@
   Integer $write_threads                = $collectd::write_threads,
 ) {
 
+  assert_private()
+
   $_conf_content = $purge_config ? {
     true    => template('collectd/collectd.conf.erb'),
     default => $conf_content,
diff --git a/manifests/install.pp b/manifests/install.pp
index 473a2ead5..5b04556b9 100644
--- a/manifests/install.pp
+++ b/manifests/install.pp
@@ -6,6 +6,8 @@
   $manage_package                           = $collectd::manage_package,
 ) {
 
+  assert_private()
+
   if $manage_package {
     package { $package_name:
       ensure          => $package_ensure,
diff --git a/manifests/service.pp b/manifests/service.pp
index 992eb5c25..54ac5113c 100644
--- a/manifests/service.pp
+++ b/manifests/service.pp
@@ -5,6 +5,8 @@
   $manage_service = $collectd::manage_service,
 ) {
 
+  assert_private()
+
   if $manage_service {
     service { 'collectd':
       ensure => $service_ensure,