Spring Boot 4 Microservices & REST APIs · Lesson

Deploying to Kubernetes Cluster

Learn to package and deploy your microservices to a Kubernetes cluster for scalable orchestration.

Deploying to Kubernetes Cluster is a free Spring Boot 4 Microservices & REST APIs lesson on CoddyKit — lesson 1 of 3. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Spring Boot 4 Microservices & REST APIs learning path, one of 3 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Why Kubernetes for Deployment?

You've built microservices and containerized them with Docker. Now, how do you manage them at scale?

Kubernetes is an open-source system for automating deployment, scaling, and management of containerized applications. It helps you run your microservices reliably.

Containerizing Your Microservice

Before deploying to Kubernetes, your Spring Boot application needs to be packaged into a Docker image. This process makes your application portable.

A Dockerfile defines how to build this image. You can think of it as a recipe for your container.

FROM openjdk:17-jdk-slim
ARG JAR_FILE=target/*.jar
COPY ${JAR_FILE} app.jar
ENTRYPOINT ["java","-jar","/app.jar"]

Kubernetes Core: Pods

The smallest deployable unit in Kubernetes is a Pod. A Pod represents a single instance of a running process in your cluster.

A Pod typically contains one application container (e.g., your Spring Boot app).
It can also contain sidecar containers for logging or monitoring.
Pods are ephemeral: if a Pod dies, Kubernetes creates a new one.

Kubernetes Core: Deployments

Directly managing Pods is tricky. That's where Deployments come in! A Deployment describes the desired state for your application.

It manages a set of identical Pods.
Handles rolling updates and rollbacks.
Ensures a specified number of Pod replicas are always running.

Think of it as the blueprint for your application instances.

Crafting Your Deployment YAML

Deployments are defined using YAML files. This manifest specifies details like the Docker image to use, the number of replicas, and resource limits.

Here's a basic example for a Spring Boot microservice:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-spring-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: my-spring-app
  template:
    metadata:
      labels:
        app: my-spring-app
    spec:
      containers:
      - name: my-spring-app
        image: your-dockerhub-user/my-spring-app:1.0
        ports:
        - containerPort: 8080

Kubernetes Core: Services

Pods are created and destroyed dynamically, so their IP addresses change. How do other services or users find them?

A Service provides a stable network endpoint for a set of Pods. It acts as a load balancer, routing traffic to healthy Pods.

Decouples clients from Pod IP addresses.
Enables communication between microservices.

Exposing Your App with a Service

To make your Spring Boot application accessible, you need a Service. We'll use a NodePort type, which exposes the service on a static port on each Node.

This allows external traffic to reach your application.

apiVersion: v1
kind: Service
metadata:
  name: my-spring-app-service
spec:
  selector:
    app: my-spring-app
  ports:
    - protocol: TCP
      port: 8080
      targetPort: 8080
  type: NodePort

Deploying Your App with Kubectl

Once your Deployment and Service YAML files are ready, you use the kubectl command-line tool to apply them to your Kubernetes cluster.

kubectl interacts with the Kubernetes API server to create or update resources.

kubectl apply -f deployment.yaml
kubectl apply -f service.yaml

Verify and Scale Your Application

After applying, you can check the status of your deployments and services:

kubectl get deployments
kubectl get pods
kubectl get services

To scale your application (e.g., to 4 instances):

kubectl scale deployment my-spring-app --replicas=4

Kubernetes Core Concepts Quiz

Test your understanding of Kubernetes deployment fundamentals.

Recap: Deploying to Kubernetes

In this lesson, you learned how to prepare your Spring Boot microservice for Kubernetes deployment and the core resources involved:

Pods: Smallest deployable units.
Deployments: Manage and scale Pods.
Services: Expose your application reliably.

You now have the foundation to deploy your containerized applications to a Kubernetes cluster!

Frequently asked questions

Is the “Deploying to Kubernetes Cluster” lesson free?

Yes — the full text of “Deploying to Kubernetes Cluster” is free to read here on the web, and the Spring Boot 4 Microservices & REST APIs course includes 3 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Spring Boot 4 Microservices & REST APIs course, upgrade to CoddyKit PRO.

What will I learn in “Deploying to Kubernetes Cluster”?

Learn to package and deploy your microservices to a Kubernetes cluster for scalable orchestration. You practise Spring Boot 4 Microservices & REST APIs with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Spring Boot 4 Microservices & REST APIs?

No prior experience is required. Spring Boot 4 Microservices & REST APIs on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 3, so you can start here or from the beginning and move at your own pace.

How long does the “Deploying to Kubernetes Cluster” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Spring Boot 4 Microservices & REST APIs lesson?

Yes. Every Spring Boot 4 Microservices & REST APIs lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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