Bhuwan Upadhyay

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Expose spring boot microservice with ingress using helm



In k8s deployment, ingress exposes HTTP and HTTPS routes from outside the cluster to services within the cluster.

In this article, I will take you through how to expose spring boot microservice for the outside world in k8s deployment using ingress.

This example needs kubectl minikube helm command-line tools in your machine.

Simple Spring Boot Microservice

Let's create one simple spring boot microservice that just returns the given name.

Initialize Project

NAME='Expose spring boot microservice with ingress using helm' && PRJ=expose-spring-boot-microservice-with-ingress-using-helm && \
mkdir -p $PRJ && cd $PRJ && \
curl https://start.spring.io/starter.tgz \
    -d dependencies=actuator,webflux \
    -d groupId=io.github.bhuwanupadhyay -d artifactId=$PRJ -d packageName=io.github.bhuwanupadhyay.example \
    -d applicationName=Spring Boot -d name=$NAME -d description=$NAME \
    -d language=kotlin -d platformVersion=2.3.1.RELEASE -d javaVersion=11 \
    -o demo.tgz && \
    tar -xzvf demo.tgz && rm -rf demo.tgz

Simple API to return given name

class NameRoutes(private val handler: NameHandler) {

    fun router() = router {
        accept(APPLICATION_JSON).nest {
            GET("/names/{given-name}", handler::findGivenName)

Containerizing Spring Boot Application

From Spring Boot 2.3.0.RELEASE the maven plugin of spring boot by default support build-image goal during execution which creates an OCI image using Cloud Native Buildpacks.


Run mvn clean install : spring boot maven plugin will create a docker image. The end part of the output log:

[INFO] Successfully built image 'docker.io/bhuwanupadhyay/expose-spring-boot-microservice-with-ingress-using-helm:0.0.1-SNAPSHOT'

To publish docker image in a registry run the following command

docker push docker.io/bhuwanupadhyay/expose-spring-boot-microservice-with-ingress-using-helm:0.0.1-SNAPSHOT

Helm Chart

To create a helm chart from your project directory run the following command.

helm create src/microservice

Replace value image repository and tag with your published docker image name and tag in src/microservice/values.yaml inside a helm chart.

  repository: docker.io/bhuwanupadhyay/expose-spring-boot-microservice-with-ingress-using-helm
  pullPolicy: IfNotPresent
  tag: '0.0.1-SNAPSHOT'

In your helm chart under src/microservice/templates/deployment.yaml change readinessProbe and livenessProbe health check settings, also modify container port to 8080 is the default for spring boot application.

  - name: http
    containerPort: 8080
    protocol: TCP
    path: /actuator/health
    port: http
  initialDelaySeconds: 30
  periodSeconds: 60
  timeoutSeconds: 5
  failureThreshold: 5
    path: /actuator/health
    port: http
  initialDelaySeconds: 30
  periodSeconds: 5
  timeoutSeconds: 5
  failureThreshold: 5

Enable Ingress in Helm

Simply modify file src/microservice/values.yaml accordingly.

  enabled: true
    kubernetes.io/ingress.class: nginx
    # kubernetes.io/tls-acme: "true"
    - host: microservice.minikube
        - '/'


Get ready for the deployment!

Start Minikube and Enable ingress

minikube start

Minikube enable addons ingress and ingress-dns in

minikube addons enable ingress
minikube addons enable ingress-dns

Helm deployment

helm upgrade \
    --install -f src/microservice/values.yaml \
    example-deployment src/microservice --force

Watch the deployment and ingress

watch kubectl get pods

Modify /etc/hosts to add your host

# Know your host and address -> Run the following command
kubectl get ingress
# Output
NAME                              CLASS    HOSTS                   ADDRESS      PORTS   AGE
example-deployment-microservice   <none>   microservice.minikube   80      63m
# Add your host -> Run the following command
sudo sed -i "$ a microservice.minikube" /etc/hosts

Test Microservice APIS

Firstly, install httpie command line tool.

sudo apt install httpie

Open New Terminal - Call microservice APIS

# GET given name
http http://microservice.minikube/names/k8sname
# Output
    "givenName": "k8sname"

We are done ! Thanks for reading. Github