Spring Boot + Kubernetes Tutorial - Service Hello World Example

In a previous tutorial we had deployed spring boot application to kubernetes pods. We were not able to access the deployed application using curl.

In this tutorial we will be developing a Nodeport service using which the external client will be able to access the deployed application.

Spring Boot + Kubernetes Tutorial
What is Kubernetes? Need for it?
Install Ubuntu on Windows using WSL 
Installing Kubectl, Minikube and Docker on Ubuntu
Create Docker Image
Deploy to Minikube Pods
Difference between ClusterIP, NodePort and LoadBalancer Service
Service Hello World Example

Implementation

In previous tutorial we had created the nodeport service configuration file as follows-

apiVersion: v1
kind: Service
metadata:
  name: employee-producer-service
spec:
  selector:
    app: boot-jar
  ports:
    - protocol: TCP
      port: 80
      targetPort: 8080
      nodePort: 30080
  type: NodePort

The above configuration file will create a service with selector tag - app: boot-jar. So the pod to which this service will be redirecting the request to should have the same tag. Also the external client will call this service using the nodeport 30080. This request will then be forwarded to service port 80 and then finally to target port 8080.

Start Minikube

minikube start --force

If we list the docker images, we can see the images we created previously

docker image ls

To use docker with minikube we will need to switch the docker context to using minikube.

eval $(minikube docker-env)

Let us now deploy the service we had created before-

kubectl apply -f service.yml

In previous tutorial we had created a pod.yml for deploying spring boot application to kupernetes pods. For this we will be modifying the pod.yml to have the same label as the service.

apiVersion: v1
kind: Pod
metadata:
  name: boot-jar
  labels:
    app: boot-jar
spec:
  containers:
  - name: boot-jar-container
    image: javainuse/employee-producer-kubernetes:latest

Delete existing pod named boot-jar that we had created earlier

kubectl delete pod boot-jar

Next we will again create the pod as follows -

kubectl apply -f pod.yml

We can check the pod logs as follows

kubectl logs boot-jar

As the pod is showing that the application has started successfully, we will test the application running in pod. For this we first need to get the minikube ip address as follows -

minikube ip

We will now make use of the minikube ip and the node port to access the service.

curl 192.168.49.2:30080/employee