Spring Boot with Kubernetes & Docker

1️⃣ Introduction

Containerization and orchestration are essential for modern application deployment. This article explores how to containerize Spring Boot applications and deploy them on Kubernetes.

Key features include:

  • Docker containerization
  • Kubernetes deployment
  • Container orchestration
  • Configuration management
  • Scaling and monitoring

2️⃣ Key Concepts & Terminology

  • Docker: Containerization platform
  • Kubernetes: Container orchestration platform
  • Pod: Smallest deployable unit in Kubernetes
  • Service: Network endpoint for accessing pods
  • ConfigMap/Secret: Configuration management in Kubernetes

3️⃣ Hands-on Implementation 🛠

🔹 Step 1: Dockerfile Creation

FROM eclipse-temurin:17-jdk-alpine
WORKDIR /app
COPY target/*.jar app.jar
EXPOSE 8080
ENTRYPOINT ["java", "-jar", "app.jar"]

# Multi-stage build for smaller image
FROM eclipse-temurin:17-jre-alpine
WORKDIR /app
COPY --from=0 /app/app.jar .
EXPOSE 8080
ENTRYPOINT ["java", "-jar", "app.jar"]

🔹 Step 2: Kubernetes Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: spring-boot-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: spring-boot-app
  template:
    metadata:
      labels:
        app: spring-boot-app
    spec:
      containers:
      - name: spring-boot-app
        image: spring-boot-app:latest
        ports:
        - containerPort: 8080
        env:
        - name: SPRING_PROFILES_ACTIVE
          value: "prod"
        resources:
          requests:
            memory: "512Mi"
            cpu: "200m"
          limits:
            memory: "1Gi"
            cpu: "500m"

🔹 Step 3: Kubernetes Service

apiVersion: v1
kind: Service
metadata:
  name: spring-boot-service
spec:
  selector:
    app: spring-boot-app
  ports:
  - port: 80
    targetPort: 8080
  type: LoadBalancer

4️⃣ Common Issues & Debugging 🐞

Common Issues and Solutions

Issue Solution
Container startup issues Check logs and health probes
Resource constraints Adjust resource requests and limits
Configuration problems Verify ConfigMap and Secret setup

5️⃣ Q&A / Frequently Asked Questions

A Pod is the smallest deployable unit in Kubernetes and can contain one or more containers. A container is the actual runtime environment for your application.

Use ConfigMaps for non-sensitive configuration and Secrets for sensitive data. Mount them as environment variables or volumes in your pods.

6️⃣ Best Practices & Pro Tips 🚀

  • Use multi-stage Docker builds
  • Implement health checks
  • Set resource limits
  • Use ConfigMaps and Secrets
  • Implement proper logging
  • Use Helm for deployment

7️⃣ Read Next 📖

8️⃣ Conclusion

Containerization and Kubernetes deployment are essential for modern Spring Boot applications. Understanding Docker and Kubernetes concepts is crucial for successful deployment.

Remember to follow best practices for containerization, resource management, and configuration handling in your Kubernetes deployments.

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