document how to add a dropin file with Hiera

admin-guide/configuration/services.md

@@ -13,31 +13,6 @@ base::services:
 ```
 The key inside is the `systemd` service name without the `.service` suffix.
 
-## Extend/Override Unit File Entries with a Dropin
-You can create a dropin file by setting `dropin` to `true` and add the content of the dropin unit file below the `options` key, as in following examples:
-```
-base::services:
-    netdata:
-        enable: true
-        dropin: true
-        options:
-            Service:
-                Environment: "FOO=bar"
-```
-or if there is more than one value for the same key:
-```
-base::services:
-    netdata:
-        enable: true
-        dropin: true
-        options:
-            Service:
-                Environment:
-                - "FOO=bar"
-                - "BIZ=buz"
-```
-
-
 ## Disabling/Stopping a Service
 
 To stop and disable an already running service, disable it in the `base::services` Hiera key with `enable: false`:
@@ -90,6 +65,14 @@ base::services:
                 RemainAfterExit: 'true'
 ```
 
+If you need to set multiple values, then put the values into an list:
+```
+Service:
+    Environment:
+        - "FOO=bar"
+        - "BIZ=buz"
+```
+
 ## Enhance a Service with a Dropin Unit File
 It is possible to fine-tune already existing `systemd` unit files with dropins. These are placed as `.conf` files in `/etc/systemd/system/$SERVICE.service.d/`.
 
@@ -99,8 +82,23 @@ base::services:
     'name_of_enhanced_service':
         enable: true
         dropin: true
-        options:
-           ...
+    options:
+        ...
 ```
+Often this is done to start the service with different options, then you need to reset the orginal value with an emty entry: 
+
+```
+base::services:
+    'name_of_enhanced_service':
+        enable: true
+        dropin: true
+        options:
+            Service:
+                ExecStart:
+                - ''
+                - '/usr/sbin/my_service --verbose'
+```
+
 If there are multiple dropins, you might also name them individually with the `dropin_name` parameter.
 
+