{{- $Values := (.helm).Values | default .Values }}
{{- $runbookUrl := ($Values.defaultRules).runbookUrl | default "https://runbooks.prometheus-operator.dev/runbooks" }}
{{- $clusterLabel := ($Values.global).clusterLabel | default "cluster" }}
{{- $additionalGroupByLabels := append $Values.defaultRules.additionalGroupByLabels $clusterLabel }}
{{- $groupLabels := join "," $additionalGroupByLabels }}
{{- $grafanaHost := ternary (index (($Values.grafana).ingress).hosts 0) (($Values.external).grafana).host ($Values.grafana).enabled }}
condition: '{{ true }}'
name: kubernetes-system-kubelet
rules:
- alert: KubeNodeNotReady
  annotations:
    description: '{{`{{`}} $labels.node {{`}}`}} has been unready for more than 15 minutes on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}}.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubenodenotready'
    summary: 'Node is not ready.'
  condition: '{{ true }}'
  expr: |-
    kube_node_status_condition{job="kube-state-metrics",condition="Ready",status="true"} == 0
    and on (node,{{ $groupLabels }})
    kube_node_spec_unschedulable{job="kube-state-metrics"} == 0
  for: 15m
  labels:
    severity: warning
- alert: KubeNodePressure
  annotations:
    description: '{{`{{`}} $labels.node {{`}}`}} on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}} has active Condition {{`{{`}} $labels.condition {{`}}`}}. This is caused by resource usage exceeding eviction thresholds.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubenodepressure'
    summary: 'Node has as active Condition.'
  condition: '{{ true }}'
  expr: |-
    kube_node_status_condition{job="kube-state-metrics",condition=~"(MemoryPressure|DiskPressure|PIDPressure)",status="true"} == 1
    and on (node,{{ $groupLabels }})
    kube_node_spec_unschedulable{job="kube-state-metrics"} == 0
  for: 10m
  labels:
    severity: info
- alert: KubeNodeUnreachable
  annotations:
    description: '{{`{{`}} $labels.node {{`}}`}} is unreachable and some workloads may be rescheduled on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}}.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubenodeunreachable'
    summary: 'Node is unreachable.'
  condition: '{{ true }}'
  expr: (kube_node_spec_taint{job="kube-state-metrics",key="node.kubernetes.io/unreachable",effect="NoSchedule"} unless ignoring(key,value) kube_node_spec_taint{job="kube-state-metrics",key=~"ToBeDeletedByClusterAutoscaler|cloud.google.com/impending-node-termination|aws-node-termination-handler/spot-itn"}) == 1
  for: 15m
  labels:
    severity: warning
- alert: KubeletTooManyPods
  annotations:
    description: 'Kubelet ''{{`{{`}} $labels.node {{`}}`}}'' is running at {{`{{`}} $value | humanizePercentage {{`}}`}} of its Pod capacity on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}}.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubelettoomanypods'
    summary: 'Kubelet is running at capacity.'
  condition: '{{ true }}'
  expr: |-
    (
      max by (instance,{{ $groupLabels }}) (
        kubelet_running_pods{job="kubelet", metrics_path="/metrics"} > 1
      )
      * on (instance,{{ $groupLabels }}) group_left(node)
      max by (instance,node,{{ $groupLabels }}) (
        kubelet_node_name{job="kubelet", metrics_path="/metrics"}
      )
    )
    / on (node,{{ $groupLabels }}) group_left()
    max by (node,{{ $groupLabels }}) (
      kube_node_status_capacity{job="kube-state-metrics", resource="pods"} != 1
    ) > 0.95
  for: 15m
  labels:
    severity: info
- alert: KubeNodeReadinessFlapping
  annotations:
    description: 'The readiness status of node {{`{{`}} $labels.node {{`}}`}} has changed {{`{{`}} $value {{`}}`}} times in the last 15 minutes on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}}.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubenodereadinessflapping'
    summary: 'Node readiness status is flapping.'
  condition: '{{ true }}'
  expr: |-
    sum(changes(kube_node_status_condition{job="kube-state-metrics",status="true",condition="Ready"}[15m])) by (node,{{ $groupLabels }}) > 2
    and on (node,{{ $groupLabels }})
    kube_node_spec_unschedulable{job="kube-state-metrics"} == 0
  for: 15m
  labels:
    severity: warning
- alert: KubeNodeEviction
  annotations:
    description: 'Node {{`{{`}} $labels.node {{`}}`}} on {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}} is evicting Pods due to {{`{{`}} $labels.eviction_signal {{`}}`}}.  Eviction occurs when eviction thresholds are crossed, typically caused by Pods exceeding RAM/ephemeral-storage limits.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubenodeeviction'
    summary: 'Node is evicting pods.'
  condition: '{{ true }}'
  expr: |-
    sum(rate(kubelet_evictions{job="kubelet", metrics_path="/metrics"}[15m])) by (eviction_signal,instance,{{ $groupLabels }})
    * on (instance,{{ $groupLabels }}) group_left(node)
    max by (instance,node,{{ $groupLabels }}) (
      kubelet_node_name{job="kubelet", metrics_path="/metrics"}
    )
    > 0
  for: 0s
  labels:
    severity: info
- alert: KubeletPlegDurationHigh
  annotations:
    description: 'The Kubelet Pod Lifecycle Event Generator has a 99th percentile duration of {{`{{`}} $value {{`}}`}} seconds on node {{`{{`}} $labels.node {{`}}`}} on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}}.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubeletplegdurationhigh'
    summary: 'Kubelet Pod Lifecycle Event Generator is taking too long to relist.'
  condition: '{{ true }}'
  expr: node_quantile:kubelet_pleg_relist_duration_seconds:histogram_quantile{quantile="0.99"} >= 10
  for: 5m
  labels:
    severity: warning
- alert: KubeletPodStartUpLatencyHigh
  annotations:
    description: 'Kubelet Pod startup 99th percentile latency is {{`{{`}} $value {{`}}`}} seconds on node {{`{{`}} $labels.node {{`}}`}} on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}}.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubeletpodstartuplatencyhigh'
    summary: 'Kubelet Pod startup latency is too high.'
  condition: '{{ true }}'
  expr: histogram_quantile(0.99, sum(rate(kubelet_pod_worker_duration_seconds_bucket{job="kubelet", metrics_path="/metrics"}[5m])) by (instance,le,{{ $groupLabels }})) * on (instance,{{ $groupLabels }}) group_left(node) kubelet_node_name{job="kubelet", metrics_path="/metrics"} > 60
  for: 15m
  labels:
    severity: warning
- alert: KubeletClientCertificateExpiration
  annotations:
    description: 'Client certificate for Kubelet on node {{`{{`}} $labels.node {{`}}`}} expires in {{`{{`}} $value | humanizeDuration {{`}}`}} on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}}.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubeletclientcertificateexpiration'
    summary: 'Kubelet client certificate is about to expire.'
  condition: '{{ true }}'
  expr: kubelet_certificate_manager_client_ttl_seconds < 604800
  labels:
    severity: warning
- alert: KubeletClientCertificateExpiration
  annotations:
    description: 'Client certificate for Kubelet on node {{`{{`}} $labels.node {{`}}`}} expires in {{`{{`}} $value | humanizeDuration {{`}}`}} on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}}.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubeletclientcertificateexpiration'
    summary: 'Kubelet client certificate is about to expire.'
  condition: '{{ true }}'
  expr: kubelet_certificate_manager_client_ttl_seconds < 86400
  labels:
    severity: critical
- alert: KubeletServerCertificateExpiration
  annotations:
    description: 'Server certificate for Kubelet on node {{`{{`}} $labels.node {{`}}`}} expires in {{`{{`}} $value | humanizeDuration {{`}}`}} on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}}.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubeletservercertificateexpiration'
    summary: 'Kubelet server certificate is about to expire.'
  condition: '{{ true }}'
  expr: kubelet_certificate_manager_server_ttl_seconds < 604800
  labels:
    severity: warning
- alert: KubeletServerCertificateExpiration
  annotations:
    description: 'Server certificate for Kubelet on node {{`{{`}} $labels.node {{`}}`}} expires in {{`{{`}} $value | humanizeDuration {{`}}`}} on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}}.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubeletservercertificateexpiration'
    summary: 'Kubelet server certificate is about to expire.'
  condition: '{{ true }}'
  expr: kubelet_certificate_manager_server_ttl_seconds < 86400
  labels:
    severity: critical
- alert: KubeletClientCertificateRenewalErrors
  annotations:
    description: 'Kubelet on node {{`{{`}} $labels.node {{`}}`}} has failed to renew its client certificate ({{`{{`}} $value | humanize {{`}}`}} errors in the last 5 minutes) on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}}.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubeletclientcertificaterenewalerrors'
    summary: 'Kubelet has failed to renew its client certificate.'
  condition: '{{ true }}'
  expr: increase(kubelet_certificate_manager_client_expiration_renew_errors[5m]) > 0
  for: 15m
  labels:
    severity: warning
- alert: KubeletServerCertificateRenewalErrors
  annotations:
    description: 'Kubelet on node {{`{{`}} $labels.node {{`}}`}} has failed to renew its server certificate ({{`{{`}} $value | humanize {{`}}`}} errors in the last 5 minutes) on cluster {{`{{`}} $labels.{{ $clusterLabel }} {{`}}`}}.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubeletservercertificaterenewalerrors'
    summary: 'Kubelet has failed to renew its server certificate.'
  condition: '{{ true }}'
  expr: increase(kubelet_server_expiration_renew_errors[5m]) > 0
  for: 15m
  labels:
    severity: warning
- alert: KubeletDown
  annotations:
    description: 'Kubelet has disappeared from Prometheus target discovery.'
    runbook_url: '{{ $runbookUrl }}/kubernetes/kubeletdown'
    summary: 'Target disappeared from Prometheus target discovery.'
  condition: '{{ ($Values.kubelet).enabled }}'
  expr: absent(up{job="kubelet", metrics_path="/metrics"} == 1)
  for: 15m
  labels:
    severity: critical