---

name: uptime-monitoring description: Implement uptime monitoring and status page systems for tracking service availability. Use when monitoring application uptime, creating status pages, or implementing health checks.

Uptime Monitoring

Overview

Set up comprehensive uptime monitoring with health checks, status pages, and incident tracking to ensure visibility into service availability.

When to Use

• Service availability tracking
• Health check implementation
• Status page creation
• Incident management
• SLA monitoring

Instructions

1. Health Check Endpoints

// Node.js health check
const express = require('express');
const app = express();

app.get('/health', (req, res) => {
  res.json({
    status: 'ok',
    timestamp: new Date().toISOString(),
    uptime: process.uptime()
  });
});

app.get('/health/deep', async (req, res) => {
  const health = {
    status: 'ok',
    checks: {
      database: 'unknown',
      cache: 'unknown',
      externalApi: 'unknown'
    }
  };

  try {
    const dbResult = await db.query('SELECT 1');
    health.checks.database = dbResult ? 'ok' : 'error';
  } catch {
    health.checks.database = 'error';
    health.status = 'degraded';
  }

  try {
    const cacheResult = await redis.ping();
    health.checks.cache = cacheResult === 'PONG' ? 'ok' : 'error';
  } catch {
    health.checks.cache = 'error';
  }

  try {
    const response = await fetch('https://api.example.com/health');
    health.checks.externalApi = response.ok ? 'ok' : 'error';
  } catch {
    health.checks.externalApi = 'error';
  }

  const statusCode = health.status === 'ok' ? 200 : 503;
  res.status(statusCode).json(health);
});

app.get('/readiness', async (req, res) => {
  try {
    const dbCheck = await db.query('SELECT 1');
    const cacheCheck = await redis.ping();

    if (dbCheck && cacheCheck === 'PONG') {
      res.json({ ready: true });
    } else {
      res.status(503).json({ ready: false });
    }
  } catch {
    res.status(503).json({ ready: false });
  }
});

app.get('/liveness', (req, res) => {
  res.json({ alive: true });
});

2. Python Health Checks

from flask import Flask, jsonify
import time

app = Flask(__name__)
startup_time = time.time()

def get_uptime():
    return int(time.time() - startup_time)

@app.route('/health')
def health():
    return jsonify({
        'status': 'ok',
        'uptime_seconds': get_uptime()
    }), 200

@app.route('/health/deep')
def health_deep():
    health_status = {
        'status': 'ok',
        'checks': {
            'database': 'unknown',
            'cache': 'unknown'
        }
    }

    try:
        db.session.execute('SELECT 1')
        health_status['checks']['database'] = 'ok'
    except:
        health_status['checks']['database'] = 'error'
        health_status['status'] = 'degraded'

    try:
        cache.get('_health')
        health_status['checks']['cache'] = 'ok'
    except:
        health_status['checks']['cache'] = 'error'

    status_code = 200 if health_status['status'] == 'ok' else 503
    return jsonify(health_status), status_code

@app.route('/readiness')
def readiness():
    try:
        db.session.execute('SELECT 1')
        return jsonify({'ready': True}), 200
    except:
        return jsonify({'ready': False}), 503

3. Uptime Monitor with Heartbeat

// heartbeat.js
const axios = require('axios');

class UptimeMonitor {
  constructor(config = {}) {
    this.checkInterval = config.checkInterval || 60000;
    this.timeout = config.timeout || 5000;
    this.endpoints = config.endpoints || [];
  }

  async checkEndpoint(endpoint) {
    const startTime = Date.now();

    try {
      const response = await axios.get(endpoint.url, {
        timeout: this.timeout,
        validateStatus: (s) => s >= 200 && s < 300
      });

      const check = {
        endpoint: endpoint.name,
        status: 'up',
        responseTime: Date.now() - startTime,
        timestamp: new Date()
      };

      await this.saveCheck(check);
      return check;
    } catch (error) {
      const check = {
        endpoint: endpoint.name,
        status: 'down',
        responseTime: Date.now() - startTime,
        timestamp: new Date(),
        error: error.message
      };

      await this.saveCheck(check);
      return check;
    }
  }

  async saveCheck(check) {
    try {
      await db.query(
        'INSERT INTO uptime_checks (endpoint, status, response_time, timestamp) VALUES (?, ?, ?, ?)',
        [check.endpoint, check.status, check.responseTime, check.timestamp]
      );
    } catch (error) {
      console.error('Failed to save check:', error);
    }
  }

  async runChecks() {
    return Promise.all(
      this.endpoints.map(e => this.checkEndpoint(e))
    );
  }

  start() {
    this.runChecks();
    this.interval = setInterval(() => this.runChecks(), this.checkInterval);
  }

  stop() {
    if (this.interval) clearInterval(this.interval);
  }

  async getStats(endpoint, hours = 24) {
    const [stats] = await db.query(`
      SELECT
        COUNT(*) as total_checks,
        SUM(CASE WHEN status = 'up' THEN 1 ELSE 0 END) as uptime_checks,
        AVG(response_time) as avg_response_time
      FROM uptime_checks
      WHERE endpoint = ? AND timestamp > DATE_SUB(NOW(), INTERVAL ? HOUR)
    `, [endpoint, hours]);
    return stats[0];
  }
}

module.exports = UptimeMonitor;

4. Public Status Page API

// status-page-api.js
const express = require('express');
const router = express.Router();

router.get('/api/status', async (req, res) => {
  try {
    const endpoints = await db.query(`
      SELECT DISTINCT endpoint FROM uptime_checks
    `);

    const status = {
      page: { name: 'My Service Status', updated_at: new Date().toISOString() },
      components: []
    };

    for (const { endpoint } of endpoints) {
      const [lastCheck] = await db.query(`
        SELECT status FROM uptime_checks
        WHERE endpoint = ? ORDER BY timestamp DESC LIMIT 1
      `, [endpoint]);

      status.components.push({
        id: endpoint,
        name: endpoint,
        status: lastCheck?.status === 'up' ? 'operational' : 'major_outage'
      });
    }

    const allUp = status.components.every(c => c.status === 'operational');
    status.status = {
      overall: allUp ? 'all_operational' : 'major_outage'
    };

    res.json(status);
  } catch (error) {
    res.status(500).json({ error: 'Failed to fetch status' });
  }
});

router.get('/api/status/uptime/:endpoint', async (req, res) => {
  try {
    const stats = await db.query(`
      SELECT
        DATE(timestamp) as date,
        COUNT(*) as total,
        SUM(CASE WHEN status = 'up' THEN 1 ELSE 0 END) as uptime
      FROM uptime_checks
      WHERE endpoint = ? AND timestamp > DATE_SUB(NOW(), INTERVAL 30 DAY)
      GROUP BY DATE(timestamp)
      ORDER BY date DESC
    `, [req.params.endpoint]);

    res.json(stats);
  } catch (error) {
    res.status(500).json({ error: 'Failed to fetch statistics' });
  }
});

module.exports = router;

5. Kubernetes Health Probes

apiVersion: apps/v1
kind: Deployment
spec:
  template:
    spec:
      containers:
      - name: api-service
        image: api-service:latest

        startupProbe:
          httpGet:
            path: /health
            port: 3000
          initialDelaySeconds: 0
          periodSeconds: 10
          failureThreshold: 30

        readinessProbe:
          httpGet:
            path: /readiness
            port: 3000
          initialDelaySeconds: 5
          periodSeconds: 5
          failureThreshold: 3

        livenessProbe:
          httpGet:
            path: /liveness
            port: 3000
          initialDelaySeconds: 15
          periodSeconds: 20
          failureThreshold: 3

Best Practices

✅ DO

• Implement comprehensive health checks
• Check all critical dependencies
• Use appropriate timeout values
• Track response times
• Store check history
• Monitor uptime trends
• Alert on status changes
• Use standard HTTP status codes

❌ DON'T

• Check only application process
• Ignore external dependencies
• Set timeouts too low
• Alert on every failure
• Use health checks for load balancing
• Expose sensitive information

SLA Compliance Calculation

function calculateSLA(upChecks, totalChecks) {
  const uptime = (upChecks / totalChecks) * 100;
  return {
    uptime_percentage: uptime.toFixed(4),
    meets_99_9: uptime >= 99.9,
    meets_99_99: uptime >= 99.99
  };
}