prometheus-operator: Post only critical alerts to Slack

prometheus-operator/application.yml

@@ -7,7 +7,14 @@ metadata:
     app.kubernetes.io/name: alertmanager
 spec:
   route:
-    receiver: 'slack-notifications'
+    routes:
+      - continue: false
+        receiver: slack-notifications
+        matchers:
+          - matchType: "="
+            name: severity
+            value: critical
+    receiver: 'null'
   receivers:
   - name: 'slack-notifications'
     slackConfigs:
@@ -33,9 +40,12 @@ kind: Alertmanager
 metadata:
   name: alertmanager
 spec:
-  alertmanagerConfigSelector:
-    matchLabels:
-      app.kubernetes.io/name: alertmanager
+  alertmanagerConfigMatcherStrategy:
+    type: None
+  alertmanagerConfigNamespaceSelector: {}
+  alertmanagerConfigSelector: {}
+  alertmanagerConfiguration:
+    name: alertmanager
   secrets:
     - slack-secrets
   nodeSelector: