aadevcloud / helm-installation

What is Helm?

Helm is often referred to as the package manager for Kubernetes. It enables you to define, install, and manage even the most complex Kubernetes applications. Helm uses a packaging format called charts, which include all the resources needed to run an application, service, or a complete cloud-native stack inside Kubernetes.

Step 1: How to Install Helm in Ubuntu?

curl https://baltocdn.com/helm/signing.asc | gpg --dearmor | sudo tee /usr/share/keyrings/helm.gpg > /dev/null
sudo apt-get install apt-transport-https --yes
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/helm.gpg] https://baltocdn.com/helm/stable/debian/ all main" | sudo tee /etc/apt/sources.list.d/helm-stable-debian.list
sudo apt-get update
sudo apt-get install helm

Step 2: Create Helm Chart Structure

Run the following command to scaffold a new Helm chart:

helm create node-app-chart

This will create a folder named node-app-chart with the initial chart structure.

Step 3: Chart Metadata (Chart.yaml)

Open Chart.yaml and modify it for your application:

apiVersion: v2
name: node-app-chart
description: A Helm chart for a Node.js application
version: 0.1.0

Step 4: Default Values (values.yaml)

Edit values.yaml to include:

replicaCount: 1

image:
  repository: ayihandocker/2-tier-flask-app:flask-app
  tag: flask-app
  pullPolicy: IfNotPresent

service:
  type: NodePort
  port: 30007
  targetPort: 8000

Step 5: Deployment Manifest (templates/deployment.yaml)

Modify deployment.yaml under templates/ to look like this:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Release.Name }}-deployment
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      app: {{ .Release.Name }}
  template:
    metadata:
      labels:
        app: {{ .Release.Name }}
    spec:
      containers:
      - name: {{ .Chart.Name }}
        image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
        imagePullPolicy: {{ .Values.image.pullPolicy }}
        ports:
        - containerPort: 8000

Step 6: Service Manifest (templates/service.yaml)

Open service.yaml under templates/ and modify it:

apiVersion: v1
kind: Service
metadata:
  name: {{ .Release.Name }}-service
spec:
  type: {{ .Values.service.type }}
  ports:
  - port: {{ .Values.service.port }}
    targetPort: {{ .Values.service.targetPort }}
    nodePort: {{ .Values.service.port }}
  selector:
    app: {{ .Release.Name }}

Step 7: Deploying the Helm Chart

Use these commands to package and deploy the chart:

Package the chart (Optional)

helm package node-app-chart

Deploy the chart

helm install my-node-app ./node-app-chart

Step 8: List the Deployment

list the charts (Optional)

helm list

Check the status

helm status <chart name>

Important Helm Commands

• helm create [CHART]: Scaffold a new Helm chart.
• helm package [CHART]: Package the chart into a chart archive.
• helm install [NAME] [CHART]: Install a Helm chart.
• helm upgrade [NAME] [CHART]: Upgrade an installed Helm chart.
• helm uninstall [NAME]: Uninstall an installed Helm chart.
• helm list: List all installed Helm charts.
• helm rollback [NAME] [REVISION]: Roll back a release to a specific revision.