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Deploying Spring Microservice on Kubernetes

March 30, 2023 / Last updated : April 22, 2023 Drona Java

Deploying Spring Microservice on Kubernetes

Spring Boot is a popular framework for building microservices, while Kubernetes is a widely used container orchestration platform. In this article, we will discuss how to deploy a Spring microservice on Kubernetes.

Prerequisites:

Basic knowledge of Spring Boot and Kubernetes
Docker installed on your machine
Access to a Kubernetes cluster

Step 1

Build the Spring Boot Application First, we need to build the Spring Boot application as a Docker image. In the project directory, create a Dockerfile with the following contents:



FROM openjdk:11-jre-slim
ADD target/my-app.jar my-app.jar
EXPOSE 8080
ENTRYPOINT ["java", "-jar", "my-app.jar"]

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FROM openjdk:11-jre-slim

ADD target/my-app.jar my-app.jar

EXPOSE 8080

ENTRYPOINT ["java", "-jar", "my-app.jar"]

Here, we are using the OpenJDK 11 runtime image, adding the Spring Boot JAR file to the image, exposing port 8080, and setting the entry point to run the JAR file.

Next, build the Docker image using the following command:



docker build -t my-app .

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docker build -t my-app .

This will create a Docker image with the tag my-app.

Step 2

Push the Docker image to a container registry Before we can deploy the Docker image to Kubernetes, we need to push it to a container registry such as Docker Hub or Google Container Registry. Make sure you are logged in to the registry and then run the following command:



docker push my-app

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docker push my-app

Step 3

Create a Kubernetes deployment In Kubernetes, a deployment manages a set of replicas of a containerized application. Create a deployment YAML file with the following contents:



apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app
        image: my-app
        ports:
        - containerPort: 8080

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apiVersion: apps/v1

kind: Deployment

metadata:

name: my-app

spec:

replicas: 1

selector:

matchLabels:

app: my-app

template:

metadata:

labels:

app: my-app

spec:

containers:

- name: my-app

image: my-app

ports:

- containerPort: 8080

This YAML file specifies that we want to create a deployment called my-app with one replica, selecting containers with the label app: my-app. The template specifies that we want to create a container with the image my-app and expose port 8080.

Run the following command to create the deployment:



kubectl apply -f deployment.yaml

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kubectl apply -f deployment.yaml

Step 4

Create a Kubernetes service A Kubernetes service is used to expose a deployment internally or externally. We need to create a service to allow other services to communicate with our Spring microservice. Create a service YAML file with the following contents:



apiVersion: v1
kind: Service
metadata:
  name: my-app
spec:
  selector:
    app: my-app
  ports:
  - name: http
    port: 8080
    targetPort: 8080
  type: ClusterIP

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apiVersion: v1

kind: Service

metadata:

name: my-app

spec:

selector:

app: my-app

ports:

- name: http

port: 8080

targetPort: 8080

type: ClusterIP

This YAML file specifies that we want to create a service called my-app, selecting containers with the label app: my-app, and exposing port 8080 internally.

Run the following command to create the service:



kubectl apply -f service.yaml

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kubectl apply -f service.yaml

Step 5

Access the Spring microservice We can now access the Spring microservice using the service IP address and port. Run the following command to get the service IP address: