Kustomize vs Helm: Kubernetes Config Approaches
Kustomize patches plain YAML with overlays (no templating); Helm packages templated charts with values and a release lifecycle.
Both produce Kubernetes manifests but philosophically differ. Kustomize keeps base YAML and layers environment overlays via strategic patches. Helm renders Go templates from a chart and values file, and manages installs/upgrades as releases.
| Kustomize | Helm | |
|---|---|---|
| Approach | Overlay/patch plain YAML | Templated charts + values |
| Templating | None (declarative patches) | Go templates |
| Packaging/sharing | Limited | Charts + repositories |
| Release lifecycle | No (apply manifests) | Yes (install/upgrade/rollback) |
| Built into kubectl | Yes (kubectl -k) | Separate tool |
Where Kustomize wins
For your own manifests across a few environments, Kustomize keeps YAML readable with no template language to learn, and it is built into kubectl. Overlays make per-environment differences explicit and reviewable. It avoids the cognitive load of Go templating.
Where Helm wins
For packaging and distributing applications, especially third-party software, Helm charts plus a values file are the de facto standard, with versioned releases, rollbacks, and a huge chart ecosystem. Conditionals and loops in templates handle highly configurable apps that overlays struggle with.
Using both
Many teams install third-party software via Helm and manage their own services with Kustomize, and some render Helm output then patch it with Kustomize. The two are frequently combined rather than chosen exclusively.
The verdict
Use Kustomize for your own manifests and simple environment overlays without templating; use Helm to package, share, and version configurable apps with a release lifecycle. Combining them is common and valid.