Interview › Kubernetes, Docker, Helm & Podman
What are the parts of a Helm chart (Chart.yaml, values.yaml, templates, _helpers.tpl)?
Kubernetes, Docker, Helm & Podman · Advanced level
Answer
A Helm chart contains Chart.yaml for metadata, values.yaml for defaults, templates for Kubernetes manifests, and helper templates such as _helpers.tpl for reusable names and labels. It can also include dependencies, tests, schemas, and CRDs.
Technical explanation
_helpers.tpl commonly centralizes fullname, labels, selector labels, and common annotations.
values.schema.json improves chart usability by validating user values before install/upgrade.
Helm separates reusable chart templates from environment-specific values and tracks release revisions in the cluster.
Always validate the rendered YAML because Kubernetes receives manifests, not templates.
Good Helm practice includes values schema, deterministic helpers, security defaults, linting, dry runs, and rollback planning.
Hands-on example
1. Create or modify a small Helm chart for this exercise: walk through Chart.yaml, values.yaml, templates, and _helpers.tpl.
2. Run helm lint, helm template, helm install --dry-run --debug, and kubeconform or an equivalent manifest validator.
3. Install to a test namespace, perform an upgrade with changed values, and inspect helm status, history, and rendered manifests.
4. Test failure and rollback behavior, then document the CI gates that would prevent the same issue in production.
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