Helm¶

Helm is the standard package manager for Kubernetes applications.

It lets you template manifests, manage configuration per environment, and track release history for upgrade and rollback workflows.

Core concepts¶

Chart: package containing templates and metadata
Values: input configuration for template rendering
Release: deployed instance of a chart in a namespace
Repository: distribution source for charts

Typical chart structure¶

my-chart/
  Chart.yaml
  values.yaml
  templates/
  charts/

Install and upgrade workflow¶

helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update
helm install redis bitnami/redis -n platform --create-namespace
helm upgrade redis bitnami/redis -n platform -f values-prod.yaml

Safe change practices¶

Before applying upgrades:

helm lint ./my-chart
helm template my-app ./my-chart -f values-prod.yaml
helm upgrade my-app ./my-chart -f values-prod.yaml --dry-run --debug

After upgrade:

helm history my-app -n platform
helm rollback my-app 3 -n platform

Values management guidance¶

keep a base values file plus environment overlays
avoid committing plaintext secrets in values files
prefer immutable image tags for release reproducibility
document required values and defaults for platform consumers

Hooks¶

Helm hooks execute Jobs at defined lifecycle points: pre-install, post-install, pre-upgrade, post-upgrade, pre-delete, post-delete, and pre-rollback.

apiVersion: batch/v1
kind: Job
metadata:
  name: db-migrate
  annotations:
    "helm.sh/hook": pre-upgrade
    "helm.sh/hook-weight": "-5"
    "helm.sh/hook-delete-policy": before-hook-creation

Hooks are commonly used for database migrations (pre-upgrade), smoke tests (post-install), and cleanup jobs (post-delete). Set hook-delete-policy: before-hook-creation to prevent accumulating old hook Jobs across releases.

Dependency management¶

Declare chart dependencies in Chart.yaml and build them during CI or packaging.

helm dependency build ./my-chart

Common operational mistakes¶

changing chart templates and values simultaneously without test rendering
treating Helm as imperative only, with no Git review process
skipping rollback rehearsal for critical services

Summary¶

Helm improves repeatability and release safety when combined with linting, templating checks, and disciplined values management.