ClickHouse 연산자 모니터링

# values.yaml — minimal override
prometheus:
  enable: true

metrics:
  enable: true
  port: 8080
  secure: true            # HTTPS with authn/authz enforced on every scrape

certManager:
  enable: true            # Issues the metrics server certificate

prometheus:
  enable: false           # Set to true to render the ServiceMonitor
  scraping_annotations: false   # Alternative: prometheus.io/scrape pod annotations

helm upgrade --install clickhouse-operator \
  oci://ghcr.io/clickhouse/clickhouse-operator-helm \
  -n clickhouse-operator-system --create-namespace \
  -f values.yaml

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: clickhouse-operator-metrics-reader
rules:
  - nonResourceURLs:
      - /metrics
    verbs:
      - get

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: prometheus-clickhouse-operator-metrics-reader
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: clickhouse-operator-metrics-reader
subjects:
  - kind: ServiceAccount
    name: <prometheus-sa>
    namespace: <prometheus-namespace>

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: <release>-controller-manager-metrics-monitor
  namespace: <operator-namespace>
  labels:
    control-plane: controller-manager
spec:
  selector:
    matchLabels:
      control-plane: controller-manager
  endpoints:
    - path: /metrics
      port: https           # "http" when metrics.secure: false
      scheme: https
      bearerTokenFile: /var/run/secrets/kubernetes.io/serviceaccount/token
      tlsConfig:
        serverName: <release>-metrics-service.<operator-namespace>.svc
        ca:
          secret:
            name: metrics-server-cert
            key: ca.crt
        cert:
          secret:
            name: metrics-server-cert
            key: tls.crt
        keySecret:
          name: metrics-server-cert
          key: tls.key

livenessProbe:
  httpGet:
    path: /healthz
    port: 8081
  initialDelaySeconds: 15
  periodSeconds: 20
readinessProbe:
  httpGet:
    path: /readyz
    port: 8081
  initialDelaySeconds: 5
  periodSeconds: 10

# Reconciliation rate per controller
sum by (controller) (rate(controller_runtime_reconcile_total[5m]))

# Error rate per controller (alert if > 0 sustained)
sum by (controller) (rate(controller_runtime_reconcile_errors_total[5m]))

# p99 reconcile latency
histogram_quantile(
  0.99,
  sum by (le, controller) (rate(controller_runtime_reconcile_time_seconds_bucket[5m]))
)

# Pending items in the work queue — a sustained value > 0 indicates a backlog,
# but short spikes during large reconciles are normal.
avg_over_time(workqueue_depth[10m])

# Reconciles that have been running for a long time
workqueue_longest_running_processor_seconds > 60

# Throttled requests to the API server
sum by (code, host) (rate(rest_client_requests_total{code=~"4..|5.."}[5m]))

# Should be exactly 1 across the replica set (Helm install enables --leader-elect by default)
sum(leader_election_master_status{name="d4ceba06.clickhouse.com"})

groups:
  - name: clickhouse-operator
    rules:
      - alert: ClickHouseOperatorReconcileErrors
        # > 0.1 errors/s sustained = > ~6 errors/min, filters transient conflicts.
        expr: sum by (controller) (rate(controller_runtime_reconcile_errors_total[5m])) > 0.1
        for: 15m
        labels:
          severity: warning
        annotations:
          summary: 'ClickHouse operator is failing to reconcile {{ $labels.controller }}'

      - alert: ClickHouseOperatorWorkqueueBacklog
        # avg_over_time avoids alerting on transient bursts during large reconciles.
        expr: avg_over_time(workqueue_depth[10m]) > 5
        for: 30m
        labels:
          severity: warning
        annotations:
          summary: 'Operator work queue backlog sustained for 30m'

      - alert: ClickHouseOperatorReconcileSlow
        expr: |
          histogram_quantile(
            0.99,
            sum by (le, controller) (rate(controller_runtime_reconcile_time_seconds_bucket[10m]))
          ) > 30
        for: 15m
        labels:
          severity: warning
        annotations:
          summary: 'p99 reconcile latency for {{ $labels.controller }} > 30s'

      - alert: ClickHouseOperatorNoLeader
        expr: absent(leader_election_master_status{name="d4ceba06.clickhouse.com"}) == 1
        for: 5m
        labels:
          severity: critical
        annotations:
          summary: 'No leader for the ClickHouse operator (HA deployment)'

NS=clickhouse-operator-system

# The metrics Service exists and selects the manager pod
kubectl -n $NS get svc -l control-plane=controller-manager

# The ServiceMonitor exists (only with prometheus.enable=true)
kubectl -n $NS get servicemonitor -l control-plane=controller-manager

# Manager pod is Ready (readiness probe answers)
kubectl -n $NS get pod -l control-plane=controller-manager

# Direct scrape from inside the cluster (with the metrics-reader binding)
kubectl -n $NS run curl-metrics --rm -it --restart=Never \
  --image=curlimages/curl:8.10.1 -- sh -c '
    TOKEN=$(cat /var/run/secrets/kubernetes.io/serviceaccount/token)
    curl -sk -H "Authorization: Bearer $TOKEN" \
      https://<release>-metrics-service.'$NS'.svc:8080/metrics \
      | head -20
  '