Deploying a Node.js To-Do App with Helm on Kubernetes

Introduction

In this guide, we will deploy a Node.js To-Do App on a Kubernetes cluster using Helm. The application runs on port 8000 and uses the Docker image sgaurav7/node-app. We will configure health checks, a NodePort service, and ensure a seamless deployment.

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1️⃣ Prerequisites

Before we begin, make sure you have:
✔ A running Kubernetes cluster
✔ Helm installed (helm version)
✔ kubectl access to your cluster

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2️⃣ Create a Helm Chart

Run the following command to create a new Helm chart:

[root@k8s-master projects]# helm create todo-app
Creating todo-app
[root@k8s-master projects]# ls
mysql  todo-app
[root@k8s-master projects]# cd todo-app/
[root@k8s-master todo-app]# ls
charts  Chart.yaml  templates  values.yaml
[root@k8s-master todo-app]#

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3️⃣ Define values.yaml

Update values.yaml with the Docker image, replicas, and NodePort service:

replicaCount: 2

image:
  repository: sgaurav7/node-app
  pullPolicy: IfNotPresent
  tag: latest

imagePullSecrets: []
nameOverride: ""
fullnameOverride: ""

serviceAccount:
  create: true
  automount: true
  annotations: {}
  name: ""

podAnnotations: {}
podLabels: {}

podSecurityContext: {}

securityContext: {}

service:
  type: NodePort
  port: 8000
  nodePort: 30007

ingress:
  enabled: false
  className: ""
  annotations: {}
  hosts:
    - host: chart-example.local
      paths:
        - path: /
          pathType: ImplementationSpecific
  tls: []

resources: {}

livenessProbe:
  httpGet:
    path: /
    port: 8000
readinessProbe:
  httpGet:
    path: /
    port: 8000

autoscaling:
  enabled: false
  minReplicas: 1
  maxReplicas: 100
  targetCPUUtilizationPercentage: 80

volumes: []

volumeMounts: []

nodeSelector: {}

tolerations: []

affinity: {}

---

4️⃣ Configure Deployment (templates/deployment.yaml)

Modify deployment.yaml to use the correct image, port, and health probes:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "todo-app.fullname" . }}
  labels:
    {{- include "todo-app.labels" . | nindent 4 }}
spec:
  {{- if not .Values.autoscaling.enabled }}
  replicas: {{ .Values.replicaCount }}
  {{- end }}
  selector:
    matchLabels:
      {{- include "todo-app.selectorLabels" . | nindent 6 }}
  template:
    metadata:
      {{- with .Values.podAnnotations }}
      annotations:
        {{- toYaml . | nindent 8 }}
      {{- end }}
      labels:
        {{- include "todo-app.labels" . | nindent 8 }}
        {{- with .Values.podLabels }}
        {{- toYaml . | nindent 8 }}
        {{- end }}
    spec:
      {{- with .Values.imagePullSecrets }}
      imagePullSecrets:
        {{- toYaml . | nindent 8 }}
      {{- end }}
      serviceAccountName: {{ include "todo-app.serviceAccountName" . }}
      {{- with .Values.podSecurityContext }}
      securityContext:
        {{- toYaml . | nindent 8 }}
      {{- end }}
      containers:
        - name: {{ .Chart.Name }}
          {{- with .Values.securityContext }}
          securityContext:
            {{- toYaml . | nindent 12 }}
          {{- end }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
          imagePullPolicy: {{ .Values.image.pullPolicy }}
          ports:
            - name: todo-port
              containerPort: {{ .Values.service.port }}
              protocol: TCP
          {{- with .Values.livenessProbe }}
          livenessProbe:
            {{- toYaml . | nindent 12 }}
          {{- end }}
          {{- with .Values.readinessProbe }}
          readinessProbe:
            {{- toYaml . | nindent 12 }}
          {{- end }}
          {{- with .Values.resources }}
          resources:
            {{- toYaml . | nindent 12 }}
          {{- end }}
          {{- with .Values.volumeMounts }}
          volumeMounts:
            {{- toYaml . | nindent 12 }}
          {{- end }}
      {{- with .Values.volumes }}
      volumes:
        {{- toYaml . | nindent 8 }}
      {{- end }}
      {{- with .Values.nodeSelector }}
      nodeSelector:
        {{- toYaml . | nindent 8 }}
      {{- end }}
      {{- with .Values.affinity }}
      affinity:
        {{- toYaml . | nindent 8 }}
      {{- end }}
      {{- with .Values.tolerations }}
      tolerations:
        {{- toYaml . | nindent 8 }}
      {{- end }}

---

5️⃣ Configure Service (templates/service.yaml)

Ensure the NodePort service exposes port 8000 correctly:

apiVersion: v1
kind: Service
metadata:
  name: {{ include "todo-app.fullname" . }}
  labels:
    {{- include "todo-app.labels" . | nindent 4 }}
spec:
  type: {{ .Values.service.type }}
  ports:
    - port: {{ .Values.service.port }}
      targetPort: 8000
      nodePort: {{ .Values.service.nodePort }}
      protocol: TCP
      name: node-port
  selector:
    {{- include "todo-app.selectorLabels" . | nindent 4 }}

---

6️⃣ Deploy the To-Do App Using Helm

First-Time Installation

[root@k8s-master todo-app]# helm install v1 . --namespace to-do --create-namespace
NAME: v1
LAST DEPLOYED: Mon Mar 17 04:03:07 2025
NAMESPACE: to-do
STATUS: deployed
REVISION: 1
NOTES:
1. Get the application URL by running these commands:
  export NODE_PORT=$(kubectl get --namespace to-do -o jsonpath="{.spec.ports[0].nodePort}" services v1-todo-app)
  export NODE_IP=$(kubectl get nodes --namespace to-do -o jsonpath="{.items[0].status.addresses[0].address}")
  echo http://$NODE_IP:$NODE_PORT
[root@k8s-master todo-app]#

Upgrade the Application

If you make any changes:

helm upgrade todo-app . -n to-do

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7️⃣ Verify the Deployment

Check Helm Release

[root@k8s-master todo-app]# helm list -n to-do
NAME    NAMESPACE       REVISION        UPDATED                                 STATUS          CHART           APP VERSION
v1      to-do           1               2025-03-17 04:03:07.477506603 -0400 EDT deployed        todo-app-0.1.0  1.16.0    
[root@k8s-master todo-app]#

Check Running Pods

[root@k8s-master todo-app]# kubectl get pods -n to-do
NAME                          READY   STATUS    RESTARTS   AGE
v1-todo-app-5c87b864c-b7c7l   1/1     Running   0          55s
v1-todo-app-5c87b864c-gk7ph   1/1     Running   0          55s
[root@k8s-master todo-app]#

Check Service

[root@k8s-master todo-app]# kubectl get svc -n to-do
NAME          TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
v1-todo-app   NodePort   10.108.87.163   <none>        8000:30007/TCP   72s
[root@k8s-master todo-app]#

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8️⃣ Access the To-Do App

Now your application is accessible via:

export NODE_PORT=$(kubectl get --namespace to-do -o jsonpath="{.spec.ports[0].nodePort}" services v1-todo-app)
export NODE_IP=$(kubectl get nodes --namespace to-do -o jsonpath="{.items[0].status.addresses[0].address}")
echo http://$NODE_IP:$NODE_PORT

📌 Replace <Node-IP> with any Kubernetes worker node's IP.

[root@k8s-master todo-app]# export NODE_PORT=$(kubectl get --namespace to-do -o jsonpath="{.spec.ports[0].nodePort}" services v1-todo-app)
[root@k8s-master todo-app]#   export NODE_IP=$(kubectl get nodes --namespace to-do -o jsonpath="{.items[0].status.addresses[0].address}")
[root@k8s-master todo-app]#   echo http://$NODE_IP:$NODE_PORT
http://10.12.23.19:30007
[root@k8s-master todo-app]#

Now our application is accessible on the mentioned URL - http://10.12.23.19:30007

Search this URL on webpage.

Hurray!! We successfully deployed our application on k8s-cluster using helm.

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✅ Summary

• Created a Helm chart for the To-Do App

• Configured health probes to ensure reliability

• Deployed the app with a NodePort service (port 8000)

• Verified everything using kubectl and helm

• Accessed the app using http://<Node-IP>:30008

🎯 Now your To-Do App is successfully running on Kubernetes using Helm! 🚀
Let me know if you need any modifications. 😊