english/.opencode/skills/devops/references/kubernetes-helm-advanced.md

Helm Advanced - Templates & Hooks

Template Variables

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "mychart.fullname" . }}
spec:
  replicas: {{ .Values.replicaCount }}
  template:
    spec:
      containers:
      - name: {{ .Chart.Name }}
        image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
        {{- if .Values.resources }}
        resources:
          {{- toYaml .Values.resources | nindent 10 }}
        {{- end }}

Helper Templates

# templates/_helpers.tpl
{{- 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 }}
{{- end }}

Hooks

apiVersion: batch/v1
kind: Job
metadata:
  name: "{{ .Release.Name }}-post-install"
  annotations:
    "helm.sh/hook": post-install
    "helm.sh/hook-delete-policy": hook-succeeded
spec:
  template:
    spec:
      containers:
      - name: post-install
        command: ["/bin/sh", "-c", "echo 'Done'"]
      restartPolicy: Never

Hook types: pre-install, post-install, pre-upgrade, post-upgrade

Packaging

helm package mychart
helm repo index . --url https://charts.example.com
helm push mychart-1.0.0.tgz oci://registry.example.com/helm
helm repo add myrepo https://charts.example.com
helm install myapp myrepo/mychart

Commands

Command	Purpose
helm create	Create
helm lint	Validate
helm template	Render
helm install	Deploy
helm upgrade	Update
helm rollback	Revert
helm uninstall	Remove