Helm: The Kubernetes Package Manager — Kubernetes Basics | CertQnA

As applications grow, the number of Kubernetes manifests grows too. A single microservice might need a Deployment, Service, Ingress, ConfigMap, HPA, ServiceAccount, and multiple Secrets. Managing, versioning, and deploying all of these manually is tedious and error-prone. Helm solves this.

What is Helm?

Helm is the package manager for Kubernetes. It introduces three concepts:

Chart: A collection of Kubernetes manifest templates bundled together. Like an apt package or npm module.
Release: A running instance of a chart deployed into a cluster. One chart can produce many releases.
Repository: A collection of charts, hosted publicly or privately.

Installing Helm

# macOS
brew install helm

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

# Verify
helm version

Core Helm Commands

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

# Search for charts
helm search repo postgres
helm search hub nginx          # search Artifact Hub

# Inspect a chart before installing
helm show values bitnami/postgresql
helm show chart bitnami/postgresql

# Install a chart (creates a release named "my-db")
helm install my-db bitnami/postgresql   --set auth.postgresPassword=secret   --namespace production

# Install with a custom values file
helm install my-db bitnami/postgresql   -f values-prod.yaml   --namespace production

# List releases
helm list -A

# Upgrade a release
helm upgrade my-db bitnami/postgresql   -f values-prod.yaml   --namespace production

# Rollback to previous revision
helm rollback my-db 1 --namespace production

# Uninstall a release
helm uninstall my-db --namespace production

Chart Structure

my-chart/
  Chart.yaml          # chart metadata (name, version, description)
  values.yaml         # default configuration values
  templates/          # Kubernetes manifest templates
    deployment.yaml
    service.yaml
    ingress.yaml
    _helpers.tpl      # template helper functions
  charts/             # chart dependencies

Template Example

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Release.Name }}-app
spec:
  replicas: {{ .Values.replicaCount }}
  template:
    spec:
      containers:
        - name: app
          image: {{ .Values.image.repository }}:{{ .Values.image.tag }}

# values.yaml
replicaCount: 2
image:
  repository: my-app
  tag: v1.0.0

Creating Your Own Chart

helm create my-app          # scaffold a new chart
helm lint my-app            # validate chart
helm template my-app ./     # render templates locally (dry run)
helm install my-app ./ --dry-run --debug   # simulate install

Popular Charts

bitnami/postgresql, bitnami/redis, bitnami/kafka — databases and message queues
ingress-nginx/ingress-nginx — NGINX Ingress Controller
cert-manager/cert-manager — automated TLS certificate management
prometheus-community/kube-prometheus-stack — full monitoring stack
argo/argo-cd — GitOps continuous delivery

Next: putting it all together — deploying a real application on Kubernetes with health checks, rolling updates, and resource management.