dtsong/helm-generation

Helm Values Generation Skill

Generate Helm values files that only override necessary defaults.

Core Principles

1. Minimal diff: Output ONLY values that differ from chart defaults
2. Proper types: Booleans as booleans, not strings
3. Constraint validation: Verify values against chart's allowed options
4. CLI args for metadata: name/namespace are CLI args, not values
5. Verification-first: Read chart defaults before generating

Process

Step 1: Analyze Chart

Before generating values, understand the chart:

# Get chart info
helm show values <chart> [--version <version>]

# Or for OCI charts
helm show values oci://registry/chart

# Check chart README for constraints
helm show readme <chart>

Gather:

[ ] Default values identified
[ ] Required values (no defaults) identified
[ ] Value constraints documented (enums, ranges)
[ ] Chart version pinned

Step 2: Generate Values

Structure:

# values.yaml
# Only override what differs from defaults

# Example: Overriding replica count (default: 1)
replicaCount: 3

# Example: Overriding image (default: nginx:latest)
image:
  repository: myregistry/myapp
  tag: "1.2.3"  # Quotes for version strings

# Example: Boolean (NOT "true" string)
autoscaling:
  enabled: true

What to EXCLUDE:

• Values matching chart defaults
• name: or namespace: (use helm install <name> -n <ns>)
• Commented-out defaults
• Redundant nested keys

Step 3: Type Handling

| YAML Type | Example | Common Mistake | |-----------|---------|----------------| | Boolean | enabled: true | enabled: "true" | | Integer | replicas: 3 | replicas: "3" | | String version | tag: "1.2.3" | tag: 1.2.3 (parsed as float) | | Null | value: null | value: "" | | List | - item | Forgetting - |

Step 4: Validation

# Lint values
helm lint <chart> -f values.yaml

# Template to verify
helm template <release> <chart> -f values.yaml

# Dry-run install
helm install <release> <chart> -f values.yaml --dry-run

Common Chart Patterns

Ingress:

ingress:
  enabled: true
  className: nginx
  hosts:
    - host: app.example.com
      paths:
        - path: /
          pathType: Prefix
  tls:
    - secretName: app-tls
      hosts:
        - app.example.com

Resources:

resources:
  requests:
    cpu: 100m
    memory: 128Mi
  limits:
    cpu: 500m
    memory: 512Mi

Service Account (with IRSA/Workload Identity):

serviceAccount:
  create: true
  annotations:
    eks.amazonaws.com/role-arn: arn:aws:iam::ACCOUNT:role/ROLE

Gotchas

• tag: 1.2.3 without quotes is parsed as a float (1.2) then truncated — always quote version strings: tag: "1.2.3"
• enabled: "true" is a string, not a boolean — Helm templates checking if .Values.enabled will always be true (non-empty string)
• Including name: or namespace: in values.yaml has no effect — these are CLI args: helm install <name> -n <ns>
• helm upgrade without --install fails if the release doesn't exist — use helm upgrade --install for idempotent deployments
• Copying all chart defaults with minor changes makes diffs unreadable and breaks on chart upgrades — only override what differs
• OCI-based charts (oci://) require helm registry login first — authentication errors are cryptic

Anti-patterns to Avoid

• Including name: or namespace: in values
• Copying all defaults with minor changes
• String booleans: "true" instead of true
• Unquoted version strings that look like numbers
• Hardcoded secrets (use external-secrets, sealed-secrets, etc.)
• Values that don't exist in the chart schema

Output Format

When generating values, output:

1. Chart analysis: What chart, version, key constraints
2. Values file: Only overridden values with comments
3. Install command: Full helm install/upgrade command
4. Validation command: How to verify before applying
5. Notes: Any external dependencies (secrets, CRDs, etc.)

Example Workflow

User: "Generate Helm values for nginx-ingress"

Response:

# values.yaml for ingress-nginx
# Chart: ingress-nginx/ingress-nginx v4.10.0
# Only non-default values shown

controller:
  replicaCount: 2

  resources:
    requests:
      cpu: 100m
      memory: 90Mi
    limits:
      cpu: 500m
      memory: 256Mi

  service:
    type: LoadBalancer

# Install command
helm install ingress-nginx ingress-nginx/ingress-nginx \
  --namespace ingress-nginx \
  --create-namespace \
  -f values.yaml

# Verify
helm template ingress-nginx ingress-nginx/ingress-nginx -f values.yaml | kubectl apply --dry-run=client -f -