Helm basics

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Lesson 09 / 15

A real app is easily 5-10 YAML files — Deployment, Service, ConfigMap, Ingress, PVC... Helm packages all of that into one versioned bundle called a chart, with variables (values.yaml) so the same chart can be deployed differently per environment.


# a chart's shape
mychart/
  Chart.yaml          # name, version
  values.yaml          # defaults — replicaCount: 3, image.tag: "1.5.0"
  templates/
    deployment.yaml     # {{ .Values.replicaCount }} etc — filled in at install time
    service.yaml
    ingress.yaml


# installing a public chart (like installing a package)
helm repo add bitnami https://charts.bitnami.com/bitnami
helm install my-redis bitnami/redis

# installing your own chart, overriding a default
helm install web ./mychart --set replicaCount=5

# upgrading, and rolling back if it goes wrong
helm upgrade web ./mychart --set image.tag=1.6.0
helm rollback web 1

helm list
helm uninstall web

Think of Helm as apt/npm, but for whole Kubernetes applications instead of single binaries or libraries — one install command, one uninstall command, and a values file standing in for all the flags you'd otherwise have to remember.

Try it yourselfRun helm show values bitnami/redis (no install needed) — it's a long list of every knob that chart exposes. That's the whole idea: sensible defaults, override only what you need.

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