Helm

# 1. Add a repository and refresh the index
helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update

# 2. Look before you install — what can this chart be configured with?
helm show values bitnami/redis | less

# 3. Install as a NAMED release. The name is how you refer to it forever.
helm install my-redis bitnami/redis \
  --namespace data --create-namespace \
  --set auth.password=... \
  --version 20.1.0            # PIN the chart version. Always.

# 4. What is installed on this cluster?
helm list -A

# Render locally — no cluster contact. Catches template errors instantly.
helm template my-redis bitnami/redis -f prod-values.yaml

# Dry run against the cluster — also runs server-side validation
helm install my-redis bitnami/redis --dry-run --debug

# See exactly what an upgrade WOULD change (needs the helm-diff plugin)
helm plugin install https://github.com/databus23/helm-diff
helm diff upgrade my-redis bitnami/redis -f prod-values.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  # include a named template from _helpers.tpl; nindent keeps YAML valid
  name: {{ include "mychart.fullname" . }}
  labels:
    {{- include "mychart.labels" . | nindent 4 }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      {{- include "mychart.selectorLabels" . | nindent 6 }}
  template:
    metadata:
      labels:
        {{- include "mychart.selectorLabels" . | nindent 8 }}
    spec:
      containers:
        - name: {{ .Chart.Name }}
          # default lets the chart work with no values supplied
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
          ports:
            - containerPort: {{ .Values.service.port }}
          {{- with .Values.resources }}
          resources:
            {{- toYaml . | nindent 12 }}
          {{- end }}

replicaCount: 2
image:
  repository: nginx
  tag: ""              # empty → falls back to Chart.appVersion
service:
  port: 80
resources:
  requests: { cpu: 100m, memory: 128Mi }
  limits:   { memory: 256Mi }

# Upgrade, or install if it does not exist yet — the CI-friendly form
helm upgrade --install my-redis bitnami/redis \
  -f prod-values.yaml \
  --version 20.1.0 \
  --atomic \                 # roll back automatically if it fails
  --wait --timeout 5m        # wait for resources to be Ready

# History and rollback
helm history my-redis
helm rollback my-redis 3     # back to revision 3