diff --git a/manifests/blackbox_exporter.pp b/manifests/blackbox_exporter.pp
index 2a5cc41d8..c85fa434d 100644
--- a/manifests/blackbox_exporter.pp
+++ b/manifests/blackbox_exporter.pp
@@ -83,6 +83,7 @@
   Boolean $manage_user                    = true,
   String[1] $os                           = downcase($facts['kernel']),
   String $extra_options                   = '',
+  Hash[String, Scalar] $env_vars          = {},
   Optional[String] $download_url          = undef,
   String[1] $config_mode                  = $prometheus::config_mode,
   String[1] $arch                         = $prometheus::real_arch,
@@ -136,6 +137,7 @@
     manage_group       => $manage_group,
     options            => $options,
     init_style         => $init_style,
+    env_vars           => $env_vars,
     service_ensure     => $service_ensure,
     service_enable     => $service_enable,
     manage_service     => $manage_service,
diff --git a/manifests/config.pp b/manifests/config.pp
index c95fd8a8b..f20088edc 100644
--- a/manifests/config.pp
+++ b/manifests/config.pp
@@ -158,6 +158,15 @@
     default => undef,
   }
 
+  if $prometheus::env_file_path {
+    file { "${prometheus::env_file_path}/prometheus":
+      mode    => '0644',
+      owner   => 'root',
+      group   => '0', # Darwin uses wheel
+      content => "ARGS='${join(sort($daemon_flags), ' ')}'\n",
+    }
+  }
+
   case $prometheus::server::init_style { # lint:ignore:case_without_default
     'upstart': {
       file { '/etc/init/prometheus.conf':
@@ -182,9 +191,10 @@
         content => epp("${module_name}/prometheus.systemd.epp", {
             'user'           => $prometheus::server::user,
             'group'          => $prometheus::server::group,
-            'daemon_flags'   => $daemon_flags,
+            'daemon_flags'   => $daemon_flags.sort,
             'max_open_files' => $max_open_files,
             'bin_dir'        => $prometheus::server::bin_dir,
+            'env_file_path'  => $prometheus::server::env_file_path,
         }),
         notify  => $notify,
       }
diff --git a/manifests/postfix_exporter.pp b/manifests/postfix_exporter.pp
index 7ec06412a..ebf819b52 100644
--- a/manifests/postfix_exporter.pp
+++ b/manifests/postfix_exporter.pp
@@ -79,6 +79,7 @@
   # exporter configuration
   String  $extra_options     = '--systemd.enable --systemd.unit=\'postfix.service\' --postfix.logfile_path=\'\'',
   Boolean $restart_on_change = true,
+  Hash[String, Scalar] $env_vars = {},
 
   # scrape job configuration
   Boolean        $export_scrape_job = false,
@@ -113,6 +114,7 @@
     manage_group       => $manage_group,
     options            => $extra_options,
     init_style         => $init_style,
+    env_vars           => $env_vars,
     service_ensure     => $service_ensure,
     service_enable     => $service_enable,
     manage_service     => $manage_service,
diff --git a/spec/classes/prometheus_spec.rb b/spec/classes/prometheus_spec.rb
index fbdae06da..ea167f1d4 100644
--- a/spec/classes/prometheus_spec.rb
+++ b/spec/classes/prometheus_spec.rb
@@ -115,9 +115,21 @@
             }
 
             it {
-              is_expected.to contain_systemd__unit_file('prometheus.service').with(
-                'content' => File.read(fixtures('files', "prometheus#{prom_major}.systemd"))
-              )
+              if ['centos-7-x86_64', 'redhat-7-x86_64'].include?(os)
+                is_expected.to contain_file('/etc/sysconfig/prometheus').with(
+                  'content' => File.read(fixtures('files', 'prometheus.default'))
+                )
+                is_expected.to contain_systemd__unit_file('prometheus.service').with(
+                  'content' => File.read(fixtures('files', 'prometheus-redhat.systemd'))
+                )
+              elsif ['debian-8-x86_64', 'debian-9-x86_64', 'ubuntu-16.04-x86_64', 'ubuntu-18.04-x86_64', 'archlinux-4-x86_64'].include?(os)
+                is_expected.to contain_file('/etc/default/prometheus').with(
+                  'content' => File.read(fixtures('files', 'prometheus.default'))
+                )
+                is_expected.to contain_systemd__unit_file('prometheus.service').with(
+                  'content' => File.read(fixtures('files', 'prometheus-debian.systemd'))
+                )
+              end
             }
             describe 'max_open_files' do
               context 'by default' do
diff --git a/spec/fixtures/files/prometheus2.systemd b/spec/fixtures/files/prometheus-debian.systemd
similarity index 65%
rename from spec/fixtures/files/prometheus2.systemd
rename to spec/fixtures/files/prometheus-debian.systemd
index 796db72d9..5089ce8d0 100644
--- a/spec/fixtures/files/prometheus2.systemd
+++ b/spec/fixtures/files/prometheus-debian.systemd
@@ -7,12 +7,8 @@ After=basic.target network.target
 [Service]
 User=prometheus
 Group=prometheus
-ExecStart=/usr/local/bin/prometheus \
-  --config.file=/etc/prometheus/prometheus.yaml \
-  --web.console.templates=/usr/local/share/prometheus/consoles \
-  --web.console.libraries=/usr/local/share/prometheus/console_libraries \
-  --storage.tsdb.path=/var/lib/prometheus \
-  --storage.tsdb.retention=360h
+EnvironmentFile=/etc/default/prometheus
+ExecStart=/usr/local/bin/prometheus $ARGS
 ExecReload=/bin/kill -HUP $MAINPID
 KillMode=process
 Restart=always
diff --git a/spec/fixtures/files/prometheus1.systemd b/spec/fixtures/files/prometheus-redhat.systemd
similarity index 64%
rename from spec/fixtures/files/prometheus1.systemd
rename to spec/fixtures/files/prometheus-redhat.systemd
index aa1a75653..0424b2a0e 100644
--- a/spec/fixtures/files/prometheus1.systemd
+++ b/spec/fixtures/files/prometheus-redhat.systemd
@@ -1,3 +1,4 @@
+# THIS FILE IS MANAGED BY PUPPET
 [Unit]
 Description=Prometheus Monitoring framework
 Wants=basic.target
@@ -6,13 +7,8 @@ After=basic.target network.target
 [Service]
 User=prometheus
 Group=prometheus
-ExecStart=/usr/local/bin/prometheus \
-  -config.file=/etc/prometheus/prometheus.yaml \
-  -web.console.templates=/usr/local/share/prometheus/consoles \
-  -web.console.libraries=/usr/local/share/prometheus/console_libraries \
-  -storage.local.path=/var/lib/prometheus \
-  -storage.local.retention=360h \
-  
+EnvironmentFile=/etc/sysconfig/prometheus
+ExecStart=/usr/local/bin/prometheus $ARGS
 ExecReload=/bin/kill -HUP $MAINPID
 KillMode=process
 Restart=always
diff --git a/spec/fixtures/files/prometheus.default b/spec/fixtures/files/prometheus.default
new file mode 100644
index 000000000..e68d2f6f7
--- /dev/null
+++ b/spec/fixtures/files/prometheus.default
@@ -0,0 +1 @@
+ARGS='--config.file=/etc/prometheus/prometheus.yaml --storage.tsdb.path=/var/lib/prometheus --storage.tsdb.retention=360h --web.console.libraries=/usr/local/share/prometheus/console_libraries --web.console.templates=/usr/local/share/prometheus/consoles'
diff --git a/templates/prometheus.systemd.epp b/templates/prometheus.systemd.epp
index 75e08998c..b6b09147f 100644
--- a/templates/prometheus.systemd.epp
+++ b/templates/prometheus.systemd.epp
@@ -3,6 +3,7 @@
       Array[String] $daemon_flags,
       Optional[Integer] $max_open_files,
       Stdlib::Absolutepath $bin_dir,
+      Optional[String] $env_file_path,
 | -%>
 # THIS FILE IS MANAGED BY PUPPET
 [Unit]
@@ -13,8 +14,13 @@ After=basic.target network.target
 [Service]
 User=<%= $user %>
 Group=<%= $group %>
+<% if $env_file_path { -%>
+EnvironmentFile=<%= $env_file_path %>/prometheus
+ExecStart=<%= $bin_dir %>/prometheus $ARGS
+<% } else { -%>
 ExecStart=<%= $bin_dir %>/prometheus \
   <%= $daemon_flags.join(" \\\n  ") %>
+<% } -%>
 ExecReload=/bin/kill -HUP $MAINPID
 KillMode=process
 Restart=always