Helm

Kubernetes package manager for application deployment

Overview

Helm is the package manager for Kubernetes. It helps you manage Kubernetes applications through Helm Charts - packages of pre-configured Kubernetes resources.

Key Concepts

Concept	Description
Chart	A package of pre-configured Kubernetes resources
Repository	A collection of charts
Release	A specific instance of a chart running in the cluster
Values	Configuration values that override chart defaults

Helm Architecture

Helm Client (CLI)
        ↓
Helm Chart (Package)
        ↓
Kubernetes API Server
        ↓
Chart Resources Deployed

Quick Start

Install Helm

# macOS
brew install helm

# Linux
curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

# Windows (Chocolatey)
choco install kubernetes-helm

# Verify
helm version

Basic Commands

# Add repository
helm repo add bitnami https://charts.bitnami.com/bitnami

# Update repositories
helm repo update

# Search for charts
helm search repo nginx

# Install chart
helm install my-release bitnami/nginx

# List releases
helm list

# Uninstall release
helm uninstall my-release

# Upgrade release
helm upgrade my-release bitnami/nginx

Chart Structure

my-chart/
├── Chart.yaml          # Chart metadata
├── values.yaml         # Default configuration values
├── values.schema.json  # Values schema (optional)
├── charts/             # Chart dependencies
├── templates/           # Kubernetes manifest templates
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── ingress.yaml
│   └── ...
└── templates/NOTES.txt # Usage notes (optional)

Using Charts

Installing from Repository

# Install with default values
helm install my-nginx bitnami/nginx

# Install with custom values
helm install my-nginx bitnami/nginx --set replicaCount=3

# Install with values file
helm install my-nginx bitnami/nginx -f custom-values.yaml

# Install in specific namespace
helm install my-nginx bitnami/nginx -n my-apps --create-namespace

Creating Custom Chart

# Create new chart
helm create my-chart

# Package chart
helm package my-chart

# Install local chart
helm install my-release ./my-chart-1.0.0.tgz

Values File

Default values.yaml

replicaCount: 1

image:
  repository: nginx
  pullPolicy: IfNotPresent
  tag: "1.25"

service:
  type: ClusterIP
  port: 80

ingress:
  enabled: false
  className: "nginx"
  hosts:
    - host: chart-example.local
      paths:
      - path: /
        pathType: Prefix

resources:
  limits:
    cpu: 100m
    memory: 128Mi
  requests:
    cpu: 100m
    memory: 128Mi

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

Custom values override

# custom-values.yaml
replicaCount: 3

image:
  tag: "1.26"

service:
  type: LoadBalancer

ingress:
  enabled: true

resources:
  limits:
    cpu: 500m
    memory: 512Mi

helm install my-release ./my-chart -f custom-values.yaml

Template Example

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "my-chart.fullname" . }}
  labels:
    {{- include "my-chart.labels" . | nindent 4 }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      {{- include "my-chart.selectorLabels" . | nindent 6 }}
  template:
    metadata:
      labels:
        {{- include "my-chart.selectorLabels" . | nindent 8 }}
    spec:
      containers:
      - name: {{ .Chart.Name }}
        image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
        imagePullPolicy: {{ .Values.image.pullPolicy }}
        ports:
        - name: http
          containerPort: 80
          protocol: TCP
        livenessProbe:
          httpGet:
            path: /
            port: http
        readinessProbe:
          httpGet:
            path: /
            port: http
        resources:
          {{- toYaml .Values.resources | nindent 10 }}

Popular Charts

Chart	Description
nginx-ingress	Ingress controller
cert-manager	TLS certificate management
prometheus	Monitoring system
grafana	Visualization dashboard
postgresql	Database
redis	Key-value store
mlflow	ML platform

Best Practices

1. Use official or trusted charts
2. Pin chart versions in production
3. Review chart manifests before installing
4. Use values files for configuration
5. Version control your values files
6. Test in non-production first

Next Steps

1. Explore Helm Charts: Artifact Hub
2. Create Custom Chart: Helm Docs
3. Practice: Deploy an application using Helm

Additional Resources

• Helm Documentation
• Artifact Hub
• Helm Charts Guide

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