diff --git a/manifests/blackbox_exporter.pp b/manifests/blackbox_exporter.pp
index d00a538aa..3739e8587 100644
--- a/manifests/blackbox_exporter.pp
+++ b/manifests/blackbox_exporter.pp
@@ -90,30 +90,30 @@
 #     preferred_ip_protocol: ip4
 class prometheus::blackbox_exporter (
   Hash $modules                       = {},
-  String $arch                        = $::prometheus::params::arch,
-  String $bin_dir                     = $::prometheus::params::bin_dir,
-  String $config_file                 = $::prometheus::params::blackbox_exporter_config_file,
-  String $config_mode                 = $::prometheus::params::config_mode,
-  String $download_extension          = $::prometheus::params::blackbox_exporter_download_extension,
-  Variant[Undef,String] $download_url = undef,
-  String $download_url_base           = $::prometheus::params::blackbox_exporter_download_url_base,
-  Array[String] $extra_groups         = $::prometheus::params::blackbox_exporter_extra_groups,
-  String $extra_options               = '',
-  String $group                       = $::prometheus::params::blackbox_exporter_group,
-  String $init_style                  = $::prometheus::params::init_style,
-  String $install_method              = $::prometheus::params::install_method,
-  Boolean $manage_group               = true,
-  Boolean $manage_service             = true,
-  Boolean $manage_user                = true,
-  String $os                          = $::prometheus::params::os,
-  String $package_ensure              = $::prometheus::params::blackbox_exporter_package_ensure,
-  String $package_name                = $::prometheus::params::blackbox_exporter_package_name,
-  Boolean $restart_on_change          = true,
-  Boolean $service_enable             = true,
-  String $service_ensure              = 'running',
-  String $service_name                = 'blackbox_exporter',
-  String $user                        = $::prometheus::params::blackbox_exporter_user,
-  String $version                     = $::prometheus::params::blackbox_exporter_version,
+  String           $arch               = $::prometheus::params::arch,
+  String           $bin_dir            = $::prometheus::params::bin_dir,
+  String           $config_file        = $::prometheus::params::blackbox_exporter_config_file,
+  String           $config_mode        = $::prometheus::params::config_mode,
+  String           $download_extension = $::prometheus::params::blackbox_exporter_download_extension,
+  Optional[String] $download_url       = undef,
+  String           $download_url_base  = $::prometheus::params::blackbox_exporter_download_url_base,
+  Array[String]    $extra_groups       = $::prometheus::params::blackbox_exporter_extra_groups,
+  String           $extra_options      = '',
+  String           $group              = $::prometheus::params::blackbox_exporter_group,
+  String           $init_style         = $::prometheus::params::init_style,
+  String           $install_method     = $::prometheus::params::install_method,
+  Boolean          $manage_group       = true,
+  Boolean          $manage_service     = true,
+  Boolean          $manage_user        = true,
+  String           $os                 = $::prometheus::params::os,
+  String           $package_ensure     = $::prometheus::params::blackbox_exporter_package_ensure,
+  String           $package_name       = $::prometheus::params::blackbox_exporter_package_name,
+  Boolean          $restart_on_change  = true,
+  Boolean          $service_enable     = true,
+  String           $service_ensure     = 'running',
+  String           $service_name       = 'blackbox_exporter',
+  String           $user               = $::prometheus::params::blackbox_exporter_user,
+  String           $version            = $::prometheus::params::blackbox_exporter_version,
 ) inherits prometheus::params {
   # Prometheus added a 'v' on the release name at 0.1.0 of blackbox
   if versioncmp ($version, '0.1.0') >= 0 {
diff --git a/manifests/elasticsearch_exporter.pp b/manifests/elasticsearch_exporter.pp
index 88dbe9a0a..0452a9d10 100644
--- a/manifests/elasticsearch_exporter.pp
+++ b/manifests/elasticsearch_exporter.pp
@@ -78,30 +78,30 @@
 #  [*version*]
 #  The binary release version
 class prometheus::elasticsearch_exporter (
-  String $arch                        = $::prometheus::params::arch,
-  String $bin_dir                     = $::prometheus::params::bin_dir,
-  String $cnf_uri                     = $::prometheus::params::elasticsearch_exporter_cnf_uri,
-  String $cnf_timeout                 = $::prometheus::params::elasticsearch_exporter_cnf_timeout,
-  String $download_extension          = $::prometheus::params::elasticsearch_exporter_download_extension,
-  Variant[Undef,String] $download_url = undef,
-  String $download_url_base           = $::prometheus::params::elasticsearch_exporter_download_url_base,
-  Array $extra_groups                 = $::prometheus::params::elasticsearch_exporter_extra_groups,
-  String $extra_options               = '',
-  String $group                       = $::prometheus::params::elasticsearch_exporter_group,
-  String $init_style                  = $::prometheus::params::init_style,
-  String $install_method              = $::prometheus::params::install_method,
-  Boolean $manage_group               = true,
-  Boolean $manage_service             = true,
-  Boolean $manage_user                = true,
-  String $os                          = $::prometheus::params::os,
-  String $package_ensure              = $::prometheus::params::elasticsearch_exporter_package_ensure,
-  String $package_name                = $::prometheus::params::elasticsearch_exporter_package_name,
-  Boolean $purge_config_dir           = true,
-  Boolean $restart_on_change          = true,
-  Boolean $service_enable             = true,
-  String $service_ensure              = 'running',
-  String $user                        = $::prometheus::params::elasticsearch_exporter_user,
-  String $version                     = $::prometheus::params::elasticsearch_exporter_version,
+  String           $arch               = $::prometheus::params::arch,
+  String           $bin_dir            = $::prometheus::params::bin_dir,
+  String           $cnf_uri            = $::prometheus::params::elasticsearch_exporter_cnf_uri,
+  String           $cnf_timeout        = $::prometheus::params::elasticsearch_exporter_cnf_timeout,
+  String           $download_extension = $::prometheus::params::elasticsearch_exporter_download_extension,
+  Optional[String] $download_url       = undef,
+  String           $download_url_base  = $::prometheus::params::elasticsearch_exporter_download_url_base,
+  Array            $extra_groups       = $::prometheus::params::elasticsearch_exporter_extra_groups,
+  String           $extra_options      = '',
+  String           $group              = $::prometheus::params::elasticsearch_exporter_group,
+  String           $init_style         = $::prometheus::params::init_style,
+  String           $install_method     = $::prometheus::params::install_method,
+  Boolean          $manage_group       = true,
+  Boolean          $manage_service     = true,
+  Boolean          $manage_user        = true,
+  String           $os                 = $::prometheus::params::os,
+  String           $package_ensure     = $::prometheus::params::elasticsearch_exporter_package_ensure,
+  String           $package_name       = $::prometheus::params::elasticsearch_exporter_package_name,
+  Boolean          $purge_config_dir   = true,
+  Boolean          $restart_on_change  = true,
+  Boolean          $service_enable     = true,
+  String           $service_ensure     = 'running',
+  String           $user               = $::prometheus::params::elasticsearch_exporter_user,
+  String           $version            = $::prometheus::params::elasticsearch_exporter_version,
 ) inherits prometheus::params {
   #Please provide the download_url for versions < 0.9.0
   $real_download_url = pick($download_url,"${download_url_base}/download/v${version}/${package_name}-${version}.${os}-${arch}.${download_extension}")
diff --git a/manifests/mongodb_exporter.pp b/manifests/mongodb_exporter.pp
index 882f16460..24cf0d0cb 100644
--- a/manifests/mongodb_exporter.pp
+++ b/manifests/mongodb_exporter.pp
@@ -72,29 +72,29 @@
 #  [*version*]
 #  The binary release version
 class prometheus::mongodb_exporter (
-  String $arch                        = $::prometheus::params::arch,
-  String $bin_dir                     = $::prometheus::params::bin_dir,
-  String $cnf_uri                     = $::prometheus::params::mongodb_exporter_cnf_uri,
-  String $download_extension          = $::prometheus::params::mongodb_exporter_download_extension,
-  Variant[Undef,String] $download_url = undef,
-  String $download_url_base           = $::prometheus::params::mongodb_exporter_download_url_base,
-  Array $extra_groups                 = $::prometheus::params::mongodb_exporter_extra_groups,
-  String $extra_options               = '',
-  String $group                       = $::prometheus::params::mongodb_exporter_group,
-  String $init_style                  = $::prometheus::params::init_style,
-  String $install_method              = $::prometheus::params::install_method,
-  Boolean $manage_group               = true,
-  Boolean $manage_service             = true,
-  Boolean $manage_user                = true,
-  String $os                          = $::prometheus::params::os,
-  String $package_ensure              = $::prometheus::params::mongodb_exporter_package_ensure,
-  String $package_name                = $::prometheus::params::mongodb_exporter_package_name,
-  Boolean $purge_config_dir           = true,
-  Boolean $restart_on_change          = true,
-  Boolean $service_enable             = true,
-  String $service_ensure              = 'running',
-  String $user                        = $::prometheus::params::mongodb_exporter_user,
-  String $version                     = $::prometheus::params::mongodb_exporter_version,
+  String           $arch               = $::prometheus::params::arch,
+  String           $bin_dir            = $::prometheus::params::bin_dir,
+  String           $cnf_uri            = $::prometheus::params::mongodb_exporter_cnf_uri,
+  String           $download_extension = $::prometheus::params::mongodb_exporter_download_extension,
+  Optional[String] $download_url       = undef,
+  String           $download_url_base  = $::prometheus::params::mongodb_exporter_download_url_base,
+  Array            $extra_groups       = $::prometheus::params::mongodb_exporter_extra_groups,
+  String           $extra_options      = '',
+  String           $group              = $::prometheus::params::mongodb_exporter_group,
+  String           $init_style         = $::prometheus::params::init_style,
+  String           $install_method     = $::prometheus::params::install_method,
+  Boolean          $manage_group       = true,
+  Boolean          $manage_service     = true,
+  Boolean          $manage_user        = true,
+  String           $os                 = $::prometheus::params::os,
+  String           $package_ensure     = $::prometheus::params::mongodb_exporter_package_ensure,
+  String           $package_name       = $::prometheus::params::mongodb_exporter_package_name,
+  Boolean          $purge_config_dir   = true,
+  Boolean          $restart_on_change  = true,
+  Boolean          $service_enable     = true,
+  String           $service_ensure     = 'running',
+  String           $user               = $::prometheus::params::mongodb_exporter_user,
+  String           $version            = $::prometheus::params::mongodb_exporter_version,
 ) inherits prometheus::params {
   #Please provide the download_url for versions < 0.9.0
   $real_download_url = pick($download_url,"${download_url_base}/download/v${version}/${package_name}-${version}.${os}-${arch}.${download_extension}")
diff --git a/manifests/pushgateway.pp b/manifests/pushgateway.pp
index 4ae3d481d..4e6eb5262 100644
--- a/manifests/pushgateway.pp
+++ b/manifests/pushgateway.pp
@@ -69,28 +69,28 @@
 #  [*version*]
 #  The binary release version
 class prometheus::pushgateway (
-  String $arch                        = $::prometheus::params::arch,
-  String $bin_dir                     = $::prometheus::params::bin_dir,
-  String $download_extension          = $::prometheus::params::pushgateway_download_extension,
-  Variant[Undef,String] $download_url = undef,
-  String $download_url_base           = $::prometheus::params::pushgateway_download_url_base,
-  Array $extra_groups                 = $::prometheus::params::pushgateway_extra_groups,
-  String $extra_options               = '',
-  String $group                       = $::prometheus::params::pushgateway_group,
-  String $init_style                  = $::prometheus::params::init_style,
-  String $install_method              = $::prometheus::params::install_method,
-  Boolean $manage_group               = true,
-  Boolean $manage_service             = true,
-  Boolean $manage_user                = true,
-  String $os                          = $::prometheus::params::os,
-  String $package_ensure              = $::prometheus::params::pushgateway_package_ensure,
-  String $package_name                = $::prometheus::params::pushgateway_package_name,
-  Boolean $restart_on_change          = true,
-  Boolean $service_enable             = true,
-  String $service_ensure              = 'running',
-  String $service_name                = 'pushgateway',
-  String $user                        = $::prometheus::params::pushgateway_user,
-  String $version                     = $::prometheus::params::pushgateway_version,
+  String           $arch               = $::prometheus::params::arch,
+  String           $bin_dir            = $::prometheus::params::bin_dir,
+  String           $download_extension = $::prometheus::params::pushgateway_download_extension,
+  Optional[String] $download_url       = undef,
+  String           $download_url_base  = $::prometheus::params::pushgateway_download_url_base,
+  Array            $extra_groups       = $::prometheus::params::pushgateway_extra_groups,
+  String           $extra_options      = '',
+  String           $group              = $::prometheus::params::pushgateway_group,
+  String           $init_style         = $::prometheus::params::init_style,
+  String           $install_method     = $::prometheus::params::install_method,
+  Boolean          $manage_group       = true,
+  Boolean          $manage_service     = true,
+  Boolean          $manage_user        = true,
+  String           $os                 = $::prometheus::params::os,
+  String           $package_ensure     = $::prometheus::params::pushgateway_package_ensure,
+  String           $package_name       = $::prometheus::params::pushgateway_package_name,
+  Boolean          $restart_on_change  = true,
+  Boolean          $service_enable     = true,
+  String           $service_ensure     = 'running',
+  String           $service_name       = 'pushgateway',
+  String           $user               = $::prometheus::params::pushgateway_user,
+  String           $version            = $::prometheus::params::pushgateway_version,
 ) inherits prometheus::params {
   # Prometheus added a 'v' on the realease name at 0.3.0
   if versioncmp ($version, '0.3.0') >= 0 {