MODULE 11 - Spring Boot Actuator and Monitoring

Welcome to Module 11! 📊

Your application is in production... but how do you know if it's working properly? Is it slow? Is it running out of memory? Spring Boot Actuator gives you the eyes to monitor your application.

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🎓 Learning Objectives

By the end of this module, you will be able to:

1. ✅ Configure Spring Boot Actuator
2. ✅ Use monitoring endpoints
3. ✅ Create custom health checks
4. ✅ Collect and expose metrics
5. ✅ Integrate Prometheus and Grafana

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📚 Prerequisites

Before starting this module, you should have:

• ✅ Completed Modules 1 to 10
• ✅ Understand the basics of HTTP
• ✅ Docker installed (for Prometheus/Grafana)
• ✅ Knowledge of basic monitoring concepts

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🗺️ Module Outline

Theoretical Part (4 chapters)

Chapter 1: Introduction to Actuator

Duration: 30 minutes

Content:

• What is Actuator?
• Installation and configuration
• Endpoint security
• Getting started

Why important? Understand the basic tool

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Chapter 2: The Endpoints

Duration: 45 minutes

Content:

• /health, /info, /env
• /beans, /mappings, /conditions
• /loggers, /heapdump, /threaddump
• Custom endpoints

Why important? Diagnose your application

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Chapter 3: Metrics with Micrometer

Duration: 1 hour

Content:

• Micrometer and registries
• Counter, Gauge, Timer, Summary
• JVM, HTTP, Database metrics
• Custom metrics
• Tags and dimensions

Why important? Measure performance

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Chapter 4: Health Checks

Duration: 45 minutes

Content:

• Native Health Indicators
• Custom health checks
• Health groups
• Liveness vs Readiness (Kubernetes)

Why important? Detect issues

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Practical Part (2 Labs)

Lab 11.1: Actuator Configuration

Duration: 1h30

Objective: Configure Actuator for an application

You will:

• Enable and secure endpoints
• Create custom health checks
• Add application information
• Test all endpoints

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Lab 11.2: Monitoring with Prometheus & Grafana

Duration: 1h30

Objective: Set up a complete monitoring stack

You will:

• Configure Prometheus
• Create Grafana dashboards
• Add business metrics
• Set up alerts

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📊 Total Duration

Type	Duration
Theory	3h (4 chapters)
Practice	3h (2 Labs)
Total	6h (~2 sessions)

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🎯 What You Will Understand

Before this Module

// Application in production... 🤞
// "Is it working?"
// "I don't know, users aren't complaining..."
// "How much memory are we using?"
// "No idea..."

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After this Module

# Check health
curl http://localhost:8080/actuator/health
{
  "status": "UP",
  "components": {
    "db": { "status": "UP" },
    "diskSpace": { "status": "UP" },
    "redis": { "status": "UP" }
  }
}

# View metrics
curl http://localhost:8080/actuator/metrics/http.server.requests
{
  "name": "http.server.requests",
  "measurements": [
    { "statistic": "COUNT", "value": 1523 },
    { "statistic": "TOTAL_TIME", "value": 45.2 }
  ]
}

Grafana Dashboard:

┌─────────────────────────────────────────────┐
│ 📊 Application Dashboard                     │
├──────────────┬──────────────┬───────────────┤
│ Requests/sec │ Latency P99  │ Error Rate    │
│     125      │    45ms      │    0.1%       │
├──────────────┴──────────────┴───────────────┤
│ [Graph: Request Rate over Time]             │
│ [Graph: JVM Memory Usage]                   │
│ [Graph: Database Connection Pool]           │
└─────────────────────────────────────────────┘

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🚀 Why This Module is Essential

1. Production Visibility

Without Actuator:
- "The application is slow" → Why?
- "It's not working anymore" → Since when? What changed?
- "We have a memory issue" → Really?

With Actuator:
- Real-time metrics
- Performance history
- Proactive alerts

2. DevOps and SRE

Kubernetes Health Probes:
  livenessProbe:
    httpGet:
      path: /actuator/health/liveness
  readinessProbe:
    httpGet:
      path: /actuator/health/readiness

→ Automatic restart if the app is dead
→ Traffic cut off if the app is not ready

3. Sought-After Skill

Job offers:
✓ "Experience with Prometheus/Grafana"
✓ "Setting up monitoring"
✓ "Application observability"
✓ "Spring Boot Actuator"

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🗺️ Training Progression

Module 11 = Observe your application in production!

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📖 How to Approach This Module

Recommended Progression

1. Chapter 1 → Install and configure Actuator
2. Chapter 2 → Explore the endpoints
3. Lab 11.1 → Practice configuration
4. Chapters 3-4 → Metrics and Health
5. Lab 11.2 → Complete Prometheus/Grafana stack

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✅ Self-Assessment

Before starting, answer:

1. Do you know what Spring Boot Actuator is? ☐ Yes ☐ No
2. Are you familiar with Prometheus? ☐ Yes ☐ No
3. Have you ever used Grafana? ☐ Yes ☐ No
4. Do you know what a health check is? ☐ Yes ☐ No

This module will make you an expert on all these topics!

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🎯 Next Step

Ready to make your application observable?

➡️ Start with Chapter 1: Introduction to Actuator

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⬅️ Back to Course Outline