Fixes a bug in the AM configuration that was causing it to crash loop. (#292)

* Fixes a misconfigured inhibit rule. AM expects a map, not a list.

* Attempts to configure target_match per the documentation.

* Uses target_match_re eliminate the dupliate key names.

* Fixes inhibit rule for snmp-exporter as well.

* Adds comments to inhibit rules on what having an empty list for 'equal' means

Author: nkinkade

config/federation/alertmanager/config.yml.template

@@ -71,20 +71,22 @@ inhibit_rules:
 
 # Various other checks rely on the script-exporter being up. If the
 # script-exporter is not up, then don't alert on those dependencies.
+# The empty `equal` parameter tells AM to not attempt a match on any other
+# labels i.e., `source_match` and `target_match_re` are sufficient.
 - source_match:
-  - alertname: 'ScriptExporterDownOrMissing'
-  target_match:
-  - alertname: 'ScriptExporterMissingMetrics'
-  - alertname: 'TooManyNdtServersDown'
+    alertname: 'ScriptExporterDownOrMissing'
+  target_match_re:
+    alertname: 'ScriptExporterMissingMetrics|TooManyNdtServersDown'
   equal: []
 
 # Don't alert on missing SNMP metrics or SNMP scraping being broken if the
-# snmp-exporter is down.
+# snmp-exporter is down. The empty `equal` parameter tells AM to not attempt a
+# match on any other labels i.e., `source_match` and `target_match_re` are
+# sufficient.
 - source_match:
-  - alertname: 'SnmpExporterDownOrMissing'
-  target_match:
-  - alertname: 'SnmpExporterMissingMetrics'
-  - alertname: 'SnmpScrapingDownAtSite'
+    alertname: 'SnmpExporterDownOrMissing'
+  target_match_re:
+    alertname: 'SnmpExporterMissingMetrics|SnmpScrapingDownAtSite'
   equal: []
 
 receivers: