9.9 Helm Package Management

Managing Complex Kubernetes Applications

Helm is the package manager for Kubernetes, making it easy to deploy and manage complex applications.

Helm Basics

Charts, Releases, and Repositories

# Install Helm
curl https://get.helm.sh/helm-v3.12.0-linux-amd64.tar.gz | tar xz
sudo mv linux-amd64/helm /usr/local/bin/

# Add chart repositories
helm repo add stable https://charts.helm.sh/stable
helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update

Installing Applications

# Install from repository
helm install my-nginx bitnami/nginx
helm install postgres bitnami/postgresql --set auth.postgresPassword=secret123

# List releases
helm list
helm status my-nginx

Creating Charts

Basic Chart Structure

# Create new chart
helm create webapp

# Chart structure
webapp/
├── Chart.yaml
├── values.yaml
├── templates/
│   ├── deployment.yaml
│   ├── service.yaml
│   └── ingress.yaml
└── charts/

Chart.yaml

# Chart metadata
apiVersion: v2
name: webapp
description: A Helm chart for web application
version: 0.1.0
appVersion: "1.0.0"

values.yaml

# Default values
replicaCount: 1

image:
  repository: webapp
  tag: "latest"
  pullPolicy: IfNotPresent

service:
  type: ClusterIP
  port: 80

ingress:
  enabled: false
  host: webapp.example.com

Templates

Templating with Go Templates

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "webapp.fullname" . }}
  labels:
    {{- include "webapp.labels" . | nindent 4 }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      {{- include "webapp.selectorLabels" . | nindent 6 }}
  template:
    metadata:
      labels:
        {{- include "webapp.selectorLabels" . | nindent 8 }}
    spec:
      containers:
        - name: {{ .Chart.Name }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
          ports:
            - name: http
              containerPort: 8080

Helpers Template

# templates/_helpers.tpl
{{- define "webapp.name" -}}
{{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" }}
{{- end }}

{{- define "webapp.fullname" -}}
{{- $name := default .Chart.Name .Values.nameOverride }}
{{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" }}
{{- end }}

Managing Releases

Deployment and Updates

# Install with custom values
helm install webapp ./webapp --set replicaCount=3
helm install webapp ./webapp -f production-values.yaml

# Upgrade releases
helm upgrade webapp ./webapp --set image.tag=v2.0.0

# Rollback
helm rollback webapp 1

# Uninstall
helm uninstall webapp

Environment-Specific Values

# production-values.yaml
replicaCount: 3

image:
  tag: "v1.2.3"

ingress:
  enabled: true
  host: myapp.company.com
  tls:
    enabled: true

resources:
  limits:
    cpu: 1000m
    memory: 1Gi

Dependencies

Chart Dependencies

# Chart.yaml
dependencies:
- name: postgresql
  version: "11.6.12"
  repository: "https://charts.bitnami.com/bitnami"
  condition: postgresql.enabled
- name: redis
  version: "16.13.2"
  repository: "https://charts.bitnami.com/bitnami"
  condition: redis.enabled

# Update dependencies
helm dependency update
helm dependency build

Testing Charts

Chart Testing

# Lint chart
helm lint ./webapp

# Dry run
helm install webapp ./webapp --dry-run --debug

# Template rendering
helm template webapp ./webapp

Test Templates

# templates/tests/test-connection.yaml
apiVersion: v1
kind: Pod
metadata:
  name: "{{ include "webapp.fullname" . }}-test"
  annotations:
    "helm.sh/hook": test
spec:
  restartPolicy: Never
  containers:
    - name: wget
      image: busybox
      command: ['wget']
      args: ['{{ include "webapp.fullname" . }}:{{ .Values.service.port }}']

# Run tests
helm test webapp

Essential Commands

# Repository management
helm repo list
helm repo add bitnami https://charts.bitnami.com/bitnami
helm search repo postgres

# Release management
helm list --all-namespaces
helm history webapp
helm get values webapp
helm get manifest webapp

# Chart development
helm create mychart
helm package mychart/
helm install mychart ./mychart-0.1.0.tgz

What’s Next?

Next, we’ll explore GitOps with ArgoCD for automated deployment workflows.