Helm Chart Builder

> Category: Engineering > Domain: Kubernetes & Helm

Overview

The Helm Chart Builder skill provides automated analysis of Helm charts including structure validation, values checking, template inspection, and dependency review. It helps teams maintain high-quality charts with correct configurations, proper security contexts, and complete documentation.

Clarify First

Before analyzing the chart, confirm these inputs. If any is unknown or vague, ASK — do not assume:

• ] Chart path — which chart directory to analyze (sets --path/--chart)
• ] Values files — which environment values files to validate (sets --values and what gets checked against best practices)
• ] Strictness — strict/lint mode and JSON for CI (sets --strict --format json and whether findings gate the pipeline)

Stop rule: ask only the 2-3 that most change the output. If the user says "just draft it," proceed and list your assumptions at the top of the artifact.

Quick Start

bash
# Analyze chart structure and quality
python scripts/chart_analyzer.py --path ./charts/my-app

# Validate values.yaml against chart requirements
python scripts/values_validator.py --chart ./charts/my-app --values values-prod.yaml

# JSON output for CI
python scripts/chart_analyzer.py --path ./charts/my-app --format json

# Validate multiple values files
python scripts/values_validator.py --chart ./charts/my-app --values values-dev.yaml values-prod.yaml

Tools Overview

chart_analyzer.py

Analyzes Helm chart structure, metadata, templates, and dependencies.

| Feature | Description | |---------|-------------| | Structure validation | Checks required files exist (Chart.yaml, values.yaml, templates/) | | Metadata check | Validates Chart.yaml fields, version format, appVersion | | Template review | Inspects templates for common patterns and issues | | Dependency analysis | Reviews subchart dependencies and version constraints | | Documentation check | Verifies NOTES.txt and README presence |

values_validator.py

Validates values files against chart expectations and Kubernetes best practices.

| Feature | Description | |---------|-------------| | Resource limits | Checks for CPU/memory requests and limits | | Security context | Validates runAsNonRoot, readOnlyRootFilesystem | | Replica count | Checks for production-appropriate replica counts | | Image tags | Flags use of latest or missing image tags | | Ingress config | Validates ingress annotations and TLS settings |

Workflows

Chart Review Workflow

1. Analyze structure - Run chart_analyzer.py to check chart organization
2. Validate defaults - Run values_validator.py against default values.yaml
3. Check environments - Validate each environment's values file
4. Review findings - Address critical issues first, then warnings
5. Re-check - Confirm fixes pass validation

Pre-Release Workflow

1. Bump version - Update Chart.yaml version and appVersion
2. Lint chart - Run chart_analyzer.py in strict mode
3. Validate all values - Check every environment's values file
4. Check dependencies - Ensure subchart versions are pinned
5. Package - Chart is ready for helm package

CI Integration

bash
# Structure check
python scripts/chart_analyzer.py --path ./charts/my-app --format json --strict

# Values validation for all environments
for env in dev staging production; do
  python scripts/values_validator.py \
    --chart ./charts/my-app \
    --values "values-${env}.yaml"
done

Reference Documentation

• Helm Best Practices - Chart structure, templates, security, dependencies

Common Patterns Quick Reference

Required Chart Structure

my-chart/
  Chart.yaml          # Required: chart metadata
  values.yaml         # Required: default values
  templates/          # Required: template directory
    deployment.yaml
    service.yaml
    _helpers.tpl      # Recommended: template helpers
    NOTES.txt         # Recommended: post-install notes
  charts/             # Optional: subchart dependencies

Values Best Practices

| Setting | Requirement | Why | |---------|------------|-----| | resources.limits | Required | Prevents resource exhaustion | | resources.requests | Required | Enables proper scheduling | | securityContext.runAsNonRoot | Required | Security baseline | | image.tag | Required (not latest) | Reproducible deployments | | replicaCount >= 2 | Recommended for prod | High availability | | ingress.tls | Recommended | Encrypted traffic |

Chart.yaml Required Fields

| Field | Description | |-------|-------------| | apiVersion | v2 for Helm 3 | | name | Chart name (lowercase) | | version | SemVer chart version | | appVersion | Application version | | description | Brief chart description |

Common Issues

| Issue | Severity | Fix | |-------|----------|-----| | Missing Chart.yaml | Critical | Add required chart metadata | | No resource limits | Warning | Set CPU/memory limits | | Latest image tag | Warning | Pin specific version | | No security context | Warning | Add runAsNonRoot: true | | Missing NOTES.txt | Info | Add post-install notes | | Unpinned dependencies | Warning | Pin subchart versions |