servicemonitorのサンプル

・ntp_exporter.py

from flask import Flask, Response
import subprocess
import os
import threading
import time

app = Flask(__name__)

# 環境変数から NTP サーバ取得（なければデフォルト）
ntp_server = os.getenv("NTP_SERVER", "ntp.nict.jp")
offset_value = 0.0
interval_seconds = 60  # 取得間隔（秒）

def get_offset():
    try:
        result = subprocess.check_output(
            ["ntpdate", "-q", ntp_server],
            stderr=subprocess.STDOUT
        ).decode()

        print("[DEBUG] ntpdate raw output:", flush=True)
        print(result, flush=True)

        for line in result.splitlines():
            # 例: "2025-07-30 12:22:41.249283 (+0000) -0.000071 +/- 0.001241 ..."
            if line and line[0].isdigit():
                parts = line.split()
                offset = float(parts[3])  # offset は 4番目（インデックス3）
                print(f"[INFO] Current offset: {offset}", flush=True)
                return offset

    except Exception as e:
        print(f"[ERROR] Failed to get NTP offset: {e}", flush=True)
    return 0.0

def update_offset_loop():
    global offset_value
    while True:
        offset_value = get_offset()
        time.sleep(interval_seconds)

@app.route("/metrics")
def metrics():
    return Response(
        f"# HELP ntp_offset_seconds Current NTP offset\n"
        f"# TYPE ntp_offset_seconds gauge\n"
        f"ntp_offset_seconds {offset_value}\n",
        mimetype="text/plain"
    )

if __name__ == "__main__":
    print(f"[INFO] Starting NTP Exporter with NTP_SERVER={ntp_server}", flush=True)

    thread = threading.Thread(target=update_offset_loop, daemon=True)
    thread.start()

    app.run(host="0.0.0.0", port=9100)

・Dockerfile

FROM python:3.9-slim

RUN apt-get update && apt-get install -y ntpdate && pip install flask && apt-get clean

COPY ntp_exporter.py /ntp_exporter.py
EXPOSE 9100

ENV NTP_SERVER=ntp.nict.jp
CMD ["python", "/ntp_exporter.py"]

・ntp-exporter-daemonset.yaml

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: ntp-exporter
  namespace: monitoring
spec:
  selector:
    matchLabels:
      app: ntp-exporter
  template:
    metadata:
      labels:
        app: ntp-exporter
    spec:
      containers:
        - name: ntp-exporter
          image: xxxxxxxxxxxx.dkr.ecr.ap-northeast-1.amazonaws.com/ntp-exporter:latest  # ← 必要に応じて修正
          imagePullPolicy: Always
          ports:
            - containerPort: 9100
              name: metrics
          env:
            - name: NTP_SERVER
              value: "ntp.nict.jp"

・ntp-exporter-service.yaml

apiVersion: v1
kind: Service
metadata:
  name: ntp-exporter
  namespace: monitoring
  labels:
    app: ntp-exporter
spec:
  selector:
    app: ntp-exporter
  ports:
    - name: metrics
      port: 9100
      targetPort: 9100

・ntp-exporter-servicemonitor.yaml

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: ntp-exporter
  namespace: monitoring
  labels:
    release: kube-prometheus-stack  # ← kube-prometheus-stack ならこのラベルが必要
spec:
  selector:
    matchLabels:
      app: ntp-exporter
  endpoints:
    - port: metrics
      interval: 30s
  namespaceSelector:
    matchNames:
      - monitoring

・README

# Docker イメージビルド＆プッシュ
docker build -t xxxxxxxxxxxx.dkr.ecr.ap-northeast-1.amazonaws.com/ntp-exporter:latest .


docker push xxxxxxxxxxxx.dkr.ecr.ap-northeast-1.amazonaws.com/ntp-exporter:latest

# Kubernetes へ適用
kubectl create ns monitoring
kubectl delete -f ntp-exporter-daemonset.yaml
kubectl apply -f ntp-exporter-daemonset.yaml
kubectl apply -f ntp-exporter-service.yaml
kubectl apply -f ntp-exporter-servicemonitor.yaml

kubectl get pod -n monitoring