Advanced Helm and OCI packaging¶

Time: 6–8 hours · Working chart: my-first-chart

Values precedence¶

From lowest to highest precedence:

chart values.yaml;
parent values targeting a dependency;
each -f file.yaml, from left to right;
--set and --set-string values.

Use helm get values RELEASE -n NAMESPACE --all to inspect computed release values. A dependency receives values beneath its dependency name or alias.

Dependencies¶

Dependencies are declared in Chart.yaml and resolved into charts/ with:

helm dependency update ./my-first-chart
helm dependency list ./my-first-chart

Chart.lock records the resolved set. Commit Chart.yaml and Chart.lock; decide consistently whether packaged dependency archives belong in source control.

Hooks¶

A hook is a Kubernetes resource annotated with an event such as pre-install, post-install, pre-upgrade, or test. Hook weights order hooks numerically from lowest to highest. Delete policies prevent completed Jobs from accumulating.

Hooks can block a release and should be small, observable, idempotent, and safe to retry.

Helm tests¶

helm test runs resources annotated with helm.sh/hook: test. A test proves only what it checks. A successful HTTP request to a Service validates discovery, routing, and an application response; it does not prove persistence, availability under load, or external ingress.

OCI charts¶

Artifact Registry stores Helm charts in Docker-format repositories as OCI artifacts. The chart name and version in Chart.yaml become the OCI artifact name and tag.

LOCATION-docker.pkg.dev/PROJECT/REPOSITORY/CHART:VERSION

Package versions are immutable learning artifacts: increment version before publishing a changed chart instead of overwriting the same tag.