Helm Cheat Sheet
Reference for Helm chart structure, templating syntax, values files, and helm CLI commands for packaging Kubernetes applications.
2 PagesIntermediateFeb 20, 2026
Chart Structure
Standard directory layout of a Helm chart.
bash
mychart/ Chart.yaml # Chart metadata (name, version) values.yaml # Default configuration values charts/ # Subcharts/dependencies templates/ deployment.yaml service.yaml _helpers.tpl # Reusable template partials .helmignore
Deployment Template
A templated Deployment manifest referencing values.
yaml
apiVersion: apps/v1kind: Deploymentmetadata: name: {{ .Release.Name }}-appspec: replicas: {{ .Values.replicaCount }} selector: matchLabels: app: {{ .Chart.Name }} template: metadata: labels: app: {{ .Chart.Name }} spec: containers: - name: {{ .Chart.Name }} image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}" ports: - containerPort: {{ .Values.service.port }}
Helm CLI
Common commands for managing releases.
bash
helm create mychart # Scaffold a new charthelm install myrelease ./mychart # Install a chart as a releasehelm upgrade myrelease ./mychart # Upgrade an existing releasehelm upgrade --install myrelease ./mychart # Install or upgradehelm rollback myrelease 1 # Roll back to revision 1helm list # List releaseshelm uninstall myrelease # Remove a releasehelm template ./mychart # Render templates locallyhelm lint ./mychart # Validate chart syntax
Key Concepts
Core Helm terminology.
- chart- A package of pre-configured Kubernetes resource templates
- release- A running instance of a chart installed into a cluster
- values.yaml- Default configuration values injected into templates
- repository- A collection of charts served over HTTP (helm repo add/update)
- hooks- Annotations that run jobs at specific points in a release lifecycle (pre-install, post-upgrade)
Named Templates in _helpers.tpl
Define reusable template partials with `define` and reference them with `include`.
yaml
{{- define "mychart.fullname" -}}{{- printf "%s-%s" .Release.Name .Chart.Name | trunc 63 | trimSuffix "-" -}}{{- end -}}{{- define "mychart.labels" -}}app.kubernetes.io/name: {{ .Chart.Name }}app.kubernetes.io/instance: {{ .Release.Name }}app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}{{- end -}}# In deployment.yaml:metadata: name: {{ include "mychart.fullname" . }} labels: {{- include "mychart.labels" . | nindent 4 }}
Chart.yaml Dependencies
Declare subcharts with conditions, tags, and aliases for optional/renamed installs.
yaml
dependencies: - name: redis version: "18.x.x" repository: "https://charts.bitnami.com/bitnami" condition: redis.enabled tags: - caching - name: postgresql version: "13.x.x" repository: "https://charts.bitnami.com/bitnami" alias: primary-db condition: postgresql.enabled# After editing Chart.yaml:# helm dependency update ./mychart -- fetch and lock into charts/# helm dependency build ./mychart -- rebuild from Chart.lock
Template Functions & Pipelines
required, default, toYaml/nindent, tpl, and range for safer, DRY-er templates.
yaml
image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"{{- $repo := required "image.repository must be set" .Values.image.repository }}resources: {{- toYaml .Values.resources | nindent 2 }}configMapData: | {{- tpl .Values.configTemplate . | nindent 2 }}env: {{- range $key, $value := .Values.env }} - name: {{ $key }} value: {{ $value | quote }} {{- end }}
Release Hook Lifecycle
Annotations that control when and how hook resources run and are cleaned up.
- helm.sh/hook- Attaches a resource to a lifecycle point: pre-install, post-install, pre-upgrade, post-upgrade, pre-delete, post-delete, test
- helm.sh/hook-weight- Integer controlling execution order among hooks at the same point; lower runs first
- helm.sh/hook-delete-policy- Controls cleanup: before-hook-creation (default), hook-succeeded, hook-failed
- helm.sh/resource-policy: keep- Prevents a resource (e.g. a PVC) from being deleted on `helm uninstall`
- helm test- Runs resources annotated with `helm.sh/hook: test` against a live release to verify it works
values.schema.json Validation
JSON Schema enforced automatically by helm install/upgrade/lint against values.yaml.
json
{ "$schema": "http://json-schema.org/draft-07/schema#", "type": "object", "required": ["image", "replicaCount"], "properties": { "replicaCount": { "type": "integer", "minimum": 1 }, "image": { "type": "object", "required": ["repository"], "properties": { "repository": { "type": "string" }, "tag": { "type": "string" } } } }}
Pro Tip
Run 'helm template' before 'helm install' to render manifests locally and catch templating errors, since Helm's error messages for broken Go template syntax are often unclear at install time.
Was this cheat sheet helpful?
Explore Topics
#Helm#HelmCheatSheet#DevOps#Intermediate#ChartStructure#DeploymentTemplate#HelmCLI#KeyConcepts#Kubernetes#CommandLine#CheatSheet#SkillVeris
