Helm Chart Builder

Helm Chart Builder

Production-grade Helm charts. Sensible defaults. Secure by design. No cargo-culting.

Opinionated Helm workflow that turns ad-hoc Kubernetes manifests into maintainable, testable, reusable charts. Covers chart structure, values design, template patterns, dependency management, and security hardening.

Not a Helm tutorial — a set of concrete decisions about how to build charts that operators trust and developers don't fight.

Slash Commands

When This Skill Activates

Recognize these patterns from the user:

• "Create a Helm chart for this service"
• "Review my Helm chart"
• "Is this chart secure?"
• "Design a values.yaml"
• "Add a subchart dependency"
• "Set up helm tests"
• "Helm best practices for [workload type]"
• Any request involving: Helm chart, values.yaml, Chart.yaml, templates, helpers, _helpers.tpl, subcharts, helm lint, helm test

If the user has a Helm chart or wants to package Kubernetes resources → this skill applies.

Workflow

/helm:create — Chart Scaffolding

1. Identify workload type

   • Web service (Deployment + Service + Ingress)
   • Worker (Deployment, no Service)
   • CronJob (CronJob + ServiceAccount)
   • Stateful service (StatefulSet + PVC + Headless Service)
   • Library chart (no templates, only helpers)

2. Scaffold chart structure

   mychart/
   ├── Chart.yaml              # Chart metadata and dependencies
   ├── values.yaml             # Default configuration
   ├── values.schema.json      # Optional: JSON Schema for values validation
   ├── .helmignore             # Files to exclude from packaging
   ├── templates/
   │   ├── _helpers.tpl        # Named templates and helper functions
   │   ├── deployment.yaml     # Workload resource
   │   ├── service.yaml        # Service exposure
   │   ├── ingress.yaml        # Ingress (if applicable)
   │   ├── serviceaccount.yaml # ServiceAccount
   │   ├── hpa.yaml            # HorizontalPodAutoscaler
   │   ├── pdb.yaml            # PodDisruptionBudget
   │   ├── networkpolicy.yaml  # NetworkPolicy
   │   ├── configmap.yaml      # ConfigMap (if needed)
   │   ├── secret.yaml         # Secret (if needed)
   │   ├── NOTES.txt           # Post-install usage instructions
   │   └── tests/
   │       └── test-connection.yaml
   └── charts/                 # Subcharts (dependencies)
   

3. Apply Chart.yaml best practices

   METADATA
   ├── apiVersion: v2 (Helm 3 only — never v1)
   ├── name: matches directory name exactly
   ├── version: semver (chart version, not app version)
   ├── appVersion: application version string
   ├── description: one-line summary of what the chart deploys
   └── type: application (or library for shared helpers)
   
   DEPENDENCIES
   ├── Pin dependency versions with ~X.Y.Z (patch-level float)
   ├── Use condition field to make subcharts optional
   ├── Use alias for multiple instances of same subchart
   └── Run helm dependency update after changes
   

4. Generate values.yaml with documentation

   • Every value has an inline comment explaining purpose and type
   • Sensible defaults that work for development
   • Override-friendly structure (flat where possible, nested only when logical)
   • No hardcoded cluster-specific values (image registry, domain, storage class)

5. Validate

   python3 scripts/chart_analyzer.py mychart/
   helm lint mychart/
   helm template mychart/ --debug
   

/helm:review — Chart Analysis

1. Check chart structure

   Check	Severity	Fix
   Missing _helpers.tpl	High	Create helpers for common labels and selectors
   No NOTES.txt	Medium	Add post-install instructions
   No .helmignore	Low	Create one to exclude .git, CI files, tests
   Missing Chart.yaml fields	Medium	Add description, appVersion, maintainers
   Hardcoded values in templates	High	Extract to values.yaml with defaults

2. Check template quality

   Check	Severity	Fix
   Missing standard labels	High	Use app.kubernetes.io/* labels via _helpers.tpl
   No resource requests/limits	Critical	Add resources section with defaults in values.yaml
   Hardcoded image tag	High	Use {{ .Values.image.repository }}:{{ .Values.image.tag }}
   No imagePullPolicy	Medium	Default to IfNotPresent, overridable
   Missing liveness/readiness probes	High	Add probes with configurable paths and ports
   No pod anti-affinity	Medium	Add preferred anti-affinity for HA
   Duplicate template code	Medium	Extract into named templates in _helpers.tpl

3. Check values.yaml quality

   python3 scripts/values_validator.py mychart/values.yaml
   

4. Generate review report

   HELM CHART REVIEW — [chart name]
   Date: [timestamp]
   
   CRITICAL: [count]
   HIGH:     [count]
   MEDIUM:   [count]
   LOW:      [count]
   
   [Detailed findings with fix recommendations]
   

/helm:security — Security Audit

1. Pod security audit

   Check	Severity	Fix
   No securityContext	Critical	Add runAsNonRoot, readOnlyRootFilesystem
   Running as root	Critical	Set runAsNonRoot: true, runAsUser: 1000
   Writable root filesystem	High	Set readOnlyRootFilesystem: true + emptyDir for tmp
   All capabilities retained	High	Drop ALL, add only specific needed caps
   Privileged container	Critical	Set privileged: false, use specific capabilities
   No seccomp profile	Medium	Set seccompProfile.type: RuntimeDefault
   allowPrivilegeEscalation true	High	Set allowPrivilegeEscalation: false

2. RBAC audit

   Check	Severity	Fix
   No ServiceAccount	Medium	Create dedicated SA, don't use default
   automountServiceAccountToken true	Medium	Set to false unless pod needs K8s API access
   ClusterRole instead of Role	Medium	Use namespace-scoped Role unless cluster-wide needed
   Wildcard permissions	Critical	Use specific resource names and verbs
   No RBAC at all	Low	Acceptable if pod doesn't need K8s API access

3. Network and secrets audit

   Check	Severity	Fix
   No NetworkPolicy	Medium	Add default-deny ingress + explicit allow rules
   Secrets in values.yaml	Critical	Use external secrets operator or sealed-secrets
   No PodDisruptionBudget	Medium	Add PDB with minAvailable for HA workloads
   hostNetwork: true	High	Remove unless absolutely required (e.g., CNI plugin)
   hostPID or hostIPC	Critical	Never use in application charts

4. Generate security report

   SECURITY AUDIT — [chart name]
   Date: [timestamp]
   
   CRITICAL: [count]
   HIGH:     [count]
   MEDIUM:   [count]
   LOW:      [count]
   
   [Detailed findings with remediation steps]
   

Tooling

scripts/chart_analyzer.py

CLI utility for static analysis of Helm chart directories.

Features:

• Chart structure validation (required files, directory layout)
• Template anti-pattern detection (hardcoded values, missing labels, no resource limits)
• Chart.yaml metadata checks
• Standard labels verification (app.kubernetes.io/*)
• Security baseline checks
• JSON and text output

Usage:

# Analyze a chart directory
python3 scripts/chart_analyzer.py mychart/

# JSON output
python3 scripts/chart_analyzer.py mychart/ --output json

# Security-focused analysis
python3 scripts/chart_analyzer.py mychart/ --security

scripts/values_validator.py

CLI utility for validating values.yaml against best practices.

Features:

• Documentation coverage (inline comments)
• Type consistency checks
• Hardcoded secrets detection
• Default value quality analysis
• Structure depth analysis
• Naming convention validation
• JSON and text output

Usage:

# Validate values.yaml
python3 scripts/values_validator.py values.yaml

# JSON output
python3 scripts/values_validator.py values.yaml --output json

# Strict mode (fail on warnings)
python3 scripts/values_validator.py values.yaml --strict

Template Patterns

Pattern 1: Standard Labels (_helpers.tpl)

{{/*
Common labels for all resources.
*/}}
{{- define "mychart.labels" -}}
helm.sh/chart: {{ include "mychart.chart" . }}
app.kubernetes.io/name: {{ include "mychart.name" . }}
app.kubernetes.io/instance: {{ .Release.Name }}
app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}
app.kubernetes.io/managed-by: {{ .Release.Service }}
{{- end }}

{{/*
Selector labels (subset of common labels — must be immutable).
*/}}
{{- define "mychart.selectorLabels" -}}
app.kubernetes.io/name: {{ include "mychart.name" . }}
app.kubernetes.io/instance: {{ .Release.Name }}
{{- end }}

Pattern 2: Conditional Resources

{{- if .Values.ingress.enabled -}}
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: {{ include "mychart.fullname" . }}
  labels:
    {{- include "mychart.labels" . | nindent 4 }}
  {{- with .Values.ingress.annotations }}
  annotations:
    {{- toYaml . | nindent 4 }}
  {{- end }}
spec:
  {{- if .Values.ingress.tls }}
  tls:
    {{- range .Values.ingress.tls }}
    - hosts:
        {{- range .hosts }}
        - {{ . | quote }}
        {{- end }}
      secretName: {{ .secretName }}
    {{- end }}
  {{- end }}
  rules:
    {{- range .Values.ingress.hosts }}
    - host: {{ .host | quote }}
      http:
        paths:
          {{- range .paths }}
          - path: {{ .path }}
            pathType: {{ .pathType }}
            backend:
              service:
                name: {{ include "mychart.fullname" $ }}
                port:
                  number: {{ $.Values.service.port }}
          {{- end }}
    {{- end }}
{{- end }}

Pattern 3: Security-Hardened Pod Spec

spec:
  serviceAccountName: {{ include "mychart.serviceAccountName" . }}
  automountServiceAccountToken: false
  securityContext:
    runAsNonRoot: true
    runAsUser: 1000
    fsGroup: 1000
    seccompProfile:
      type: RuntimeDefault
  containers:
    - name: {{ .Chart.Name }}
      securityContext:
        allowPrivilegeEscalation: false
        readOnlyRootFilesystem: true
        capabilities:
          drop:
            - ALL
      image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
      imagePullPolicy: {{ .Values.image.pullPolicy }}
      resources:
        {{- toYaml .Values.resources | nindent 8 }}
      volumeMounts:
        - name: tmp
          mountPath: /tmp
  volumes:
    - name: tmp
      emptyDir: {}

Values Design Principles

STRUCTURE
├── Flat over nested (image.tag > container.spec.image.tag)
├── Group by resource (service.*, ingress.*, resources.*)
├── Use enabled: true/false for optional resources
├── Document every key with inline YAML comments
└── Provide sensible development defaults

NAMING
├── camelCase for keys (replicaCount, not replica_count)
├── Boolean keys: use adjectives (enabled, required) not verbs
├── Nested keys: max 3 levels deep
└── Match upstream conventions (image.repository, image.tag, image.pullPolicy)

ANTI-PATTERNS
├── Hardcoded cluster URLs or domains
├── Secrets as default values
├── Empty strings where null is correct
├── Deeply nested structures (>3 levels)
├── Undocumented values
└── values.yaml that doesn't work without overrides

Dependency Management

SUBCHARTS
├── Use Chart.yaml dependencies (not requirements.yaml — Helm 3)
├── Pin versions: version: ~15.x.x (patch float)
├── Use condition: to make optional: condition: postgresql.enabled
├── Use alias: for multiple instances of same chart
├── Override subchart values under subchart name key in values.yaml
└── Run helm dependency update before packaging

LIBRARY CHARTS
├── type: library in Chart.yaml — no templates directory
├── Export named templates only — no rendered resources
├── Use for shared labels, annotations, security contexts
└── Version independently from application charts

Proactive Triggers

Flag these without being asked:

• No _helpers.tpl → Create one. Every chart needs standard labels and fullname helpers.
• Hardcoded image tag in template → Extract to values.yaml. Tags must be overridable.
• No resource requests/limits → Add them. Pods without limits can starve the node.
• Running as root → Add securityContext. No exceptions for production charts.
• No NOTES.txt → Create one. Users need post-install instructions.
• Secrets in values.yaml defaults → Remove them. Use placeholders with comments explaining how to provide secrets.
• No liveness/readiness probes → Add them. Kubernetes needs to know if the pod is healthy.
• Missing app.kubernetes.io labels → Add via _helpers.tpl. Required for proper resource tracking.

Installation

One-liner (any tool)

git clone https://github.com/alirezarezvani/claude-skills.git
cp -r claude-skills/engineering/helm-chart-builder ~/.claude/skills/

Multi-tool install

./scripts/convert.sh --skill helm-chart-builder --tool codex|gemini|cursor|windsurf|openclaw

OpenClaw

clawhub install cs-helm-chart-builder

Related Skills

• senior-devops — Broader DevOps scope (CI/CD, IaC, monitoring). Complementary — use helm-chart-builder for chart-specific work, senior-devops for pipeline and infrastructure.
• docker-development — Container building. Complementary — docker-development builds the images, helm-chart-builder deploys them to Kubernetes.
• ci-cd-pipeline-builder — Pipeline construction. Complementary — helm-chart-builder defines the deployment artifact, ci-cd-pipeline-builder automates its delivery.
• senior-security — Application security. Complementary — helm-chart-builder covers Kubernetes-level security (RBAC, pod security), senior-security covers application-level threats.

Source: alirezarezvani/claude-skills → engineering/helm-chart-builder/skills/helm-chart-builder/SKILL.md