groups:
- name: alertmanager.rules
  rules:
  - alert: AlertmanagerFailedReload
    annotations:
      description: Configuration has failed to load for {{$labels.instance}}.
      summary: Reloading an Alertmanager configuration has failed.
    expr: |
      # Without max_over_time, failed scrapes could create false negatives, see
      # https://www.robustperception.io/alerting-on-gauges-in-prometheus-2-0 for details.
      max_over_time(alertmanager_config_last_reload_successful{job="alertmanager"}[5m]) == 0
    for: 10m
    labels:
      severity: critical
  - alert: AlertmanagerMembersInconsistent
    annotations:
      description: Alertmanager {{$labels.instance}} has only found {{ $value }} members
        of the {{$labels.job}} cluster.
      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"}[5m])
      < on (job) group_left
        count by (job) (max_over_time(alertmanager_cluster_members{job="alertmanager"}[5m]))
    for: 15m
    labels:
      severity: critical
  - alert: AlertmanagerFailedToSendAlerts
    annotations:
      description: Alertmanager {{$labels.instance}} failed to send {{ $value | humanizePercentage
        }} of notifications to {{ $labels.integration }}.
      summary: An Alertmanager instance failed to send notifications.
    expr: |
      (
        rate(alertmanager_notifications_failed_total{job="alertmanager"}[5m])
      /
        rate(alertmanager_notifications_total{job="alertmanager"}[5m])
      )
      > 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
        }}.
      summary: All Alertmanager instances in a cluster failed to send notifications
        to a critical integration.
    expr: |
      min by (job, integration) (
        rate(alertmanager_notifications_failed_total{job="alertmanager", integration=~`.*`}[5m])
      /
        rate(alertmanager_notifications_total{job="alertmanager", integration=~`.*`}[5m])
      )
      > 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 {{ $value | humanizePercentage
        }}.
      summary: All Alertmanager instances in a cluster failed to send notifications
        to a non-critical integration.
    expr: |
      min by (job, integration) (
        rate(alertmanager_notifications_failed_total{job="alertmanager", integration!~`.*`}[5m])
      /
        rate(alertmanager_notifications_total{job="alertmanager", integration!~`.*`}[5m])
      )
      > 0.01
    for: 5m
    labels:
      severity: warning
  - alert: AlertmanagerConfigInconsistent
    annotations:
      description: Alertmanager instances within the {{$labels.job}} cluster have
        different configurations.
      summary: Alertmanager instances within the same cluster have different configurations.
    expr: |
      count by (job) (
        count_values by (job) ("config_hash", alertmanager_config_hash{job="alertmanager"})
      )
      != 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.'
      summary: Half or more of the Alertmanager instances within the same cluster
        are down.
    expr: |
      (
        count by (job) (
          avg_over_time(up{job="alertmanager"}[5m]) < 0.5
        )
      /
        count by (job) (
          up{job="alertmanager"}
        )
      )
      >= 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.'
      summary: Half or more of the Alertmanager instances within the same cluster
        are crashlooping.
    expr: |
      (
        count by (job) (
          changes(process_start_time_seconds{job="alertmanager"}[10m]) > 4
        )
      /
        count by (job) (
          up{job="alertmanager"}
        )
      )
      >= 0.5
    for: 5m
    labels:
      severity: critical