---
conf:
  prometheus:
    rules:
      alertmanager:
        groups:
        - name: alertmanager.rules
          rules:
          - alert: AlertmanagerConfigInconsistent
            expr: count_values("config_hash", alertmanager_config_hash) BY (service) / ON(service) GROUP_LEFT() label_replace(prometheus_operator_alertmanager_spec_replicas, "service", "alertmanager-$1", "alertmanager", "(.*)") != 1
            for: 5m
            labels:
              severity: critical
            annotations:
              description: The configuration of the instances of the Alertmanager cluster `{{$labels.service}}` are out of sync.
              summary: Alertmanager configurations are inconsistent
          - alert: AlertmanagerDownOrMissing
            expr: label_replace(prometheus_operator_alertmanager_spec_replicas, "job", "alertmanager-$1", "alertmanager", "(.*)") / ON(job) GROUP_RIGHT() sum(up) BY (job) != 1
            for: 5m
            labels:
              severity: warning
            annotations:
              description: An unexpected number of Alertmanagers are scraped or Alertmanagers disappeared from discovery.
              summary: Alertmanager down or not discovered
          - alert: FailedReload
            expr: alertmanager_config_last_reload_successful == 0
            for: 10m
            labels:
              severity: warning
            annotations:
              description: Reloading Alertmanager's configuration has failed for {{ $labels.namespace }}/{{ $labels.pod }}.
              summary: Alertmanager configuration reload has failed
...