add dns record missing alert

Signed-off-by: craig <cbrookes@redhat.com>

examples/alerts/kustomization.yaml

@@ -5,3 +5,4 @@ resources:
   - prometheusrules_policies_missing.yaml
   - slo-availability.yaml
   - slo-latency.yaml
+  - orphan_records.yaml

examples/alerts/orphan_records.yaml

@@ -0,0 +1,18 @@
+apiVersion: monitoring.coreos.com/v1
+kind: PrometheusRule
+metadata:
+  name: dns-records-rules
+  namespace: monitoring
+spec:
+  groups:
+  - name: dns_records
+    rules:
+    - alert: PossibleOrphanedDNSRecords
+      expr: |
+        sum(count by(rootDomain) (kuadrant_dnsrecord_status_root_domain_owners) / count by(rootDomain) (kuadrant_dnsrecord_status) - count by(rootDomain) (kuadrant_dnsrecord_status) ) > 0
+      for: 5m
+      labels:
+        severity: warning
+      annotations:
+        summary: "The number of DNS Owners is greater than the number of records for root domain '{{ $labels.rootDomain }}'"
+        description: "This alert fires if the number of owners (controller collaborating on a record set) is greater than the number of records. This may mean a record has been left behind in the provider due to a failed delete"     

examples/alerts/prometheusrules_policies_missing.yaml

@@ -54,4 +54,4 @@ spec:
         severity: warning
       annotations:
         summary: "No RateLimitPolicy targeting HTTPRoute '{{ $labels.httproute_name }}'"
-        description: "This alert fires if a HTTPRoute does not have an associated RateLimitPolicy."
+        description: "This alert fires if a HTTPRoute does not have an associated RateLimitPolicy."