Change - Use systemd drop-in directory for override settings

The .include directive has been deprecated and support for it may
be removed in a future systemd release.  Drop-in directories are
supported on all current RedHat, Fedora, and Gentoo releases.

This branch contains changes to support this feature and disables
the old behavior of using Include directives on RedHat based nodes.

Author: Michael Watters

manifests/server/config.pp

@@ -205,48 +205,50 @@
     }
   }
 
-  if $facts['os']['family'] == 'RedHat' {
-    if $facts['os']['release']['full'] =~ /^7|^8/ or $facts['os']['name'] == 'Fedora' {
+  # RHEL 7 and 8 both support drop-in files for systemd units.  The old include directive is deprecated and may be removed in future systemd releases.
+  # Gentoo also supports drop-in files.
+  if $facts['os']['family'] in ['RedHat', 'Gentoo'] and $facts['service_provider'] == 'systemd' {
       # Template uses:
-      # - $::operatingsystem
+      # - $facts['os']['name']
+      # - $facts['os']['release']['major']
       # - $service_name
       # - $port
       # - $datadir
-      file { 'systemd-override':
-        ensure  => file,
-        path    => "/etc/systemd/system/${service_name}.service",
-        owner   => root,
-        group   => root,
-        content => template('postgresql/systemd-override.erb'),
-        notify  => [Exec['restart-systemd'], Class['postgresql::server::service']],
-        before  => Class['postgresql::server::reload'],
-      }
-      exec { 'restart-systemd':
-        command     => 'systemctl daemon-reload',
-        refreshonly => true,
-        path        => '/bin:/usr/bin:/usr/local/bin',
-      }
+      # - @extra_systemd_config
+
+    if (versioncmp($facts['puppetversion'], '5.0.0') <= 0) {
+      $systemd_notify = [Exec['restart-systemd'], Class['postgresql::server::service']]
     }
-  }
-  elsif $facts['os']['family'] == 'Gentoo' {
-    # Template uses:
-    # - $::operatingsystem
-    # - $service_name
-    # - $port
-    # - $datadir
-    file { 'systemd-override':
-      ensure  => file,
-      path    => "/etc/systemd/system/${service_name}.service",
-      owner   => root,
-      group   => root,
-      content => template('postgresql/systemd-override.erb'),
-      notify  => [Exec['restart-systemd'], Class['postgresql::server::service']],
-      before  => Class['postgresql::server::reload'],
-    }
-    exec { 'restart-systemd':
-      command     => 'systemctl daemon-reload',
-      refreshonly => true,
-      path        => '/bin:/usr/bin:/usr/local/bin',
+    else {
+      $systemd_notify = Class['postgresql::server::service']
+    }
+
+    file {
+      default:
+          ensure => file,
+          owner  => root,
+          group  => root,
+          notify => $systemd_notify,
+          before => Class['postgresql::server::reload'],
+
+      ;
+
+      'systemd-conf-dir':
+          ensure => directory,
+          path   => "/etc/systemd/system/${service_name}.service.d",
+      ;
+
+      'systemd-override':
+          path    => "/etc/systemd/system/${service_name}.service.d/${service_name}.conf",
+          content => template('postgresql/systemd-override.erb'),
+          require => File['systemd-conf-dir'],
+      ;
+
+      # Remove old unit file to avoid conflicts
+      'old-systemd-override':
+          ensure => absent,
+          path   => "/etc/systemd/system/${service_name}.service",
+      ;
     }
   }
 }