Systemd Unit Failed Ignore list

docs/admin-guide/configuration/monitoring/icinga2.md

@@ -123,7 +123,7 @@ Whenever you have a use case which is not covered yet, please talk to us.
 
 Most checks can have custom parameters. The variables you can adapt you find as "Custom Variables" in the page of given service. In Hiera you can add below the key `icinga2::service_check::customize` as multi level hash the service name and below the variable name with the new values.
 
-### Example "CPU Usage"
+### Example "CPU Usage" Customization
 
 Lets look at the example of `CPU Usage` "service":
 
@@ -146,7 +146,7 @@ icinga2::service_check::customize:
 
 If it is a Linuxfabrik plugin, you find a link at "Notes" which points to the documentation of the check. This might shed more light on the effect of these variables.
 
-### Example "Kernel Ring Buffer (dmesg)'"
+### Example "Kernel Ring Buffer (dmesg)" Message Ignore List Customization
 Another check which can easily have false alerts, but also has a big potential to signal severe kernel or hardware issues, is the check of the kernel log (dmesg).
 
 If you conclude that a given message can savely be ingored, you may add it onto the ignore list, where a partial string match will make it ignored in the future:
@@ -164,6 +164,17 @@ Note that you can reset this check after dealing with it by executing on the nod
 dmesg --clear
 ```
 
+### Example "Systemd Units Failed" Message Ignore List Customization
+It migth also be OK if some Systemd (Service) Units fail:
+
+```
+icinga2::service_check::customize:
+  'Systemd Units Failed':
+	  systemd_units_failed_ignore:
+		  - 'pli-gpfs-module-updater.service'
+```
+
+
 ## Extra Checks
 
 ### Fully Custom Checks