What is Helm?

Helm is a package manager for Kubernetes that simplifies application deployment, management, and versioning. It uses Helm charts, which are pre-configured application resources, to automate the installation and upgrade of Kubernetes applications.

Why is Helm so Important?

Helm streamlines Kubernetes deployments by enabling templated configurations, easy upgrades, and rollbacks. It enhances consistency, reusability, and automation, making it essential for managing complex Kubernetes applications efficiently.

Demo for Creating a Helm Chart

Git Repositories

Helm-demo Repo https://github.com/sanju2/helm-demo.git

Falsk Application https://github.com/sanju2/demo-apps/tree/master/flask-app

Step 1 - Create an EKS Cluster using eksctl.

Step 2 - Create a Helm Repository

helm create helm-demo

Step 3 - Delete all items inside the ‘templates’ folder and copy the following three files.

#deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mydeployment
  namespace: {{ .Values.namespace }}
  labels:
    app: {{ .Values.appName }}
spec:
  replicas: 5
  selector:
    matchLabels:
      app: {{ .Values.appName }}
      tier: frontend
  template:
    metadata:
      labels:
        app: {{ .Values.appName }}
        tier: frontend
    spec: # Pod spec
      containers:
      - name: mycontainer
        image: "{{ .Values.image.name }}:{{ .Values.image.tag }}"
        ports:
        - containerPort: 80
        envFrom:
        - configMapRef:
            name: {{ .Values.configmap.name }}
        resources:
          requests:
            memory: "16Mi" 
            cpu: "50m"
          limits:
            memory: "128Mi"
            cpu: "100m"

#service.yaml
apiVersion: v1
kind: Service
metadata:
  name: {{ .Values.appName }}
  namespace: {{ .Values.namespace }}
  labels:
    app: {{ .Values.appName }}
spec:
  ports:
  - port: 5000
    protocol: TCP
    name: flask
  selector:
    app: {{ .Values.appName }}
    tier: frontend
  type: NodePort

#configmap.yaml
kind: ConfigMap 
apiVersion: v1 
metadata:
  name: {{ .Values.configmap.name }}
  namespace: {{ .Values.namespace }}
data:
  BG_COLOR: '#12181b'
  FONT_COLOR: '#FFFFFF'
  CUSTOM_HEADER: {{ .Values.configmap.data.CUSTOM_HEADER }}

Step 4 - Replace the values.yaml file with the following file.

#values.yaml
appName: helm-demo

namespace: default

configmap:
  name: helmappconfigmapv1.1
  data: 
    CUSTOM_HEADER: 'Happy helming!!'

image:
  name: lasanthasanjeewa/flask-demo-app
  tag: v2

Step 5 - Execute the Helm install command.

helm install helm-demo-release helm-demo/ --values helm-demo/values.yaml

Step 6 - Access the application.

kubectl get svc
kubectl port-forward svc/helm-demo 8080:5000

Step 7 - Upgrade Helm.

helm upgrade helm-demo-release helm-demo/ --values helm-demo/values.yaml

Step 8 - Create a Development Step.

kubectl create ns dev
helm install helm-demo-release-dev helm-demo/ --values helm-demo/values.yaml -f webapp1/values-dev.yaml -n dev

Step 9 - Add a NOTES.txt file for additional notes. Create a file inside the ‘templates’ folder and add the following content.

#NOTES.txt
servicename=$(k get service -l "app={{ .Values.appName }}" -o jsonpath="{.items[0].metadata.name}")
kubectl --namespace {{ .Values.namespace}} port-forward service/{{ .Values.appName }} 8181:5000

Finally, you can access the development application.

kubectl get svc -n dev
kubectl port-forward svc/helm-demo 8181:5000 -n dev

References

https://helm.sh/docs/

Thanks for reading the Article.

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