# kube_prometheus_alertmanager-prometheusRule.yaml
apiVersion: monitoring.coreos.com/v1
kind: PrometheusRule
metadata:
  labels:
    app.kubernetes.io/component: alert-router
    app.kubernetes.io/instance: main
    app.kubernetes.io/name: alertmanager
    app.kubernetes.io/part-of: kube-prometheus
    app.kubernetes.io/version: 0.31.1
    prometheus: k8s
    role: alert-rules
  name: alertmanager-main-rules
  namespace: monitoring
spec:
  groups:
  - name: alertmanager.rules
    rules:
    - alert: AlertmanagerFailedReload
      annotations:
        description: Configuration has failed to load for {{ $labels.namespace }}/{{ $labels.pod}}.
        runbook_url: https://runbooks.prometheus-operator.dev/runbooks/alertmanager/alertmanagerfailedreload
        summary: Reloading an Alertmanager configuration has failed.
      expr: |
        # Without max_over_time, failed scrapes could create false negatives, see
        # https://www.robustperception.io/alerting-on-gauges-in-prometheus-2-0 for details.
        max_over_time(alertmanager_config_last_reload_successful{job="alertmanager-main",container="alertmanager",namespace="monitoring"}[5m]) == 0
      for: 10m
      labels:
        severity: critical
    - alert: AlertmanagerMembersInconsistent
      annotations:
        description: Alertmanager {{ $labels.namespace }}/{{ $labels.pod}} has only found {{ $value }} members of the {{$labels.job}} cluster.
        runbook_url: https://runbooks.prometheus-operator.dev/runbooks/alertmanager/alertmanagermembersinconsistent
        summary: A member of an Alertmanager cluster has not found all other cluster members.
      expr: |
        # Without max_over_time, failed scrapes could create false negatives, see
        # https://www.robustperception.io/alerting-on-gauges-in-prometheus-2-0 for details.
          max_over_time(alertmanager_cluster_members{job="alertmanager-main",container="alertmanager",namespace="monitoring"}[5m])
        < on (namespace,service) group_left
          count by (namespace,service) (max_over_time(alertmanager_cluster_members{job="alertmanager-main",container="alertmanager",namespace="monitoring"}[5m]))
      for: 15m
      labels:
        severity: critical
    - alert: AlertmanagerFailedToSendAlerts
      annotations:
        description: Alertmanager {{ $labels.namespace }}/{{ $labels.pod}} failed to send {{ $value | humanizePercentage }} of notifications to {{ $labels.integration }}.
        runbook_url: https://runbooks.prometheus-operator.dev/runbooks/alertmanager/alertmanagerfailedtosendalerts
        summary: An Alertmanager instance failed to send notifications.
      expr: |
        (
          rate(alertmanager_notifications_failed_total{job="alertmanager-main",container="alertmanager",namespace="monitoring"}[15m])
        /
          ignoring (reason) group_left rate(alertmanager_notifications_total{job="alertmanager-main",container="alertmanager",namespace="monitoring"}[15m])
        )
        > 0.01
      for: 5m
      labels:
        severity: warning
    - alert: AlertmanagerClusterFailedToSendAlerts
      annotations:
        description: The minimum notification failure rate to {{ $labels.integration }} sent from any instance in the {{$labels.job}} cluster is {{ $value | humanizePercentage }}.
        runbook_url: https://runbooks.prometheus-operator.dev/runbooks/alertmanager/alertmanagerclusterfailedtosendalerts
        summary: All Alertmanager instances in a cluster failed to send notifications to a critical integration.
      expr: |
        min by (namespace,service, integration) (
          rate(alertmanager_notifications_failed_total{job="alertmanager-main",container="alertmanager",namespace="monitoring", integration=~`.*`}[15m])
        /
          ignoring (reason) group_left rate(alertmanager_notifications_total{job="alertmanager-main",container="alertmanager",namespace="monitoring", integration=~`.*`}[15m]) > 0
        )
        > 0.01
      for: 5m
      labels:
        severity: critical
    - alert: AlertmanagerClusterFailedToSendAlerts
      annotations:
        description: The minimum notification failure rate to {{ $labels.integration }} sent from any instance in the {{$labels.job}} cluster is {{ $value | humanizePercentage }}.
        runbook_url: https://runbooks.prometheus-operator.dev/runbooks/alertmanager/alertmanagerclusterfailedtosendalerts
        summary: All Alertmanager instances in a cluster failed to send notifications to a non-critical integration.
      expr: |
        min by (namespace,service, integration) (
          rate(alertmanager_notifications_failed_total{job="alertmanager-main",container="alertmanager",namespace="monitoring", integration!~`.*`}[15m])
        /
          ignoring (reason) group_left rate(alertmanager_notifications_total{job="alertmanager-main",container="alertmanager",namespace="monitoring", integration!~`.*`}[15m]) > 0
        )
        > 0.01
      for: 5m
      labels:
        severity: warning
    - alert: AlertmanagerConfigInconsistent
      annotations:
        description: Alertmanager instances within the {{$labels.job}} cluster have different configurations.
        runbook_url: https://runbooks.prometheus-operator.dev/runbooks/alertmanager/alertmanagerconfiginconsistent
        summary: Alertmanager instances within the same cluster have different configurations.
      expr: |
        count by (namespace,service) (
          count_values by (namespace,service) ("config_hash", alertmanager_config_hash{job="alertmanager-main",container="alertmanager",namespace="monitoring"})
        )
        != 1
      for: 20m
      labels:
        severity: critical
    - alert: AlertmanagerClusterDown
      annotations:
        description: '{{ $value | humanizePercentage }} of Alertmanager instances within the {{$labels.job}} cluster have been up for less than half of the last 5m.'
        runbook_url: https://runbooks.prometheus-operator.dev/runbooks/alertmanager/alertmanagerclusterdown
        summary: Half or more of the Alertmanager instances within the same cluster are down.
      expr: |
        (
          count by (namespace,service) (
            avg_over_time(up{job="alertmanager-main",container="alertmanager",namespace="monitoring"}[5m]) < 0.5
          )
        /
          count by (namespace,service) (
            up{job="alertmanager-main",container="alertmanager",namespace="monitoring"}
          )
        )
        >= 0.5
      for: 5m
      labels:
        severity: critical
    - alert: AlertmanagerClusterCrashlooping
      annotations:
        description: '{{ $value | humanizePercentage }} of Alertmanager instances within the {{$labels.job}} cluster have restarted at least 5 times in the last 10m.'
        runbook_url: https://runbooks.prometheus-operator.dev/runbooks/alertmanager/alertmanagerclustercrashlooping
        summary: Half or more of the Alertmanager instances within the same cluster are crashlooping.
      expr: |
        (
          count by (namespace,service) (
            changes(process_start_time_seconds{job="alertmanager-main",container="alertmanager",namespace="monitoring"}[10m]) > 4
          )
        /
          count by (namespace,service) (
            up{job="alertmanager-main",container="alertmanager",namespace="monitoring"}
          )
        )
        >= 0.5
      for: 5m
      labels:
        severity: critical