Helm vs Kustomize: Which for Kubernetes in CI?
Helm packages and templates Kubernetes apps; Kustomize patches plain YAML with overlays - and many teams use both.
Helm is a Kubernetes package manager that templates manifests into versioned, releasable charts. Kustomize layers environment-specific overlays onto base YAML without templating, and is built into kubectl.
| Helm | Kustomize | |
|---|---|---|
| Approach | Templating + packaging | Overlays / patches on YAML |
| Packaging / releases | Charts, versioned releases | No native packaging |
| Templating | Go templates | None (declarative patches) |
| Built into kubectl | No | Yes (kubectl -k) |
| Best for | Distributable apps, complex config | Env-specific tweaks to known YAML |
In CI
Helm fits when you package and distribute apps or need versioned releases and rollbacks; charts encapsulate complex, parameterized config. Kustomize fits when you maintain plain YAML and just need clean per-environment overlays, with no templating language to learn and native kubectl support. A common CI pattern: render with helm template or kustomize build, then apply the resulting manifests.
Choosing for pipelines
Distributing third-party apps or managing complex parameterized config with release tracking: Helm. Customizing your own known manifests per environment: Kustomize. They compose well - Helm for packaging, Kustomize for last-mile overlays.
The verdict
Packaging/releasing apps or heavy parameterization: Helm. Overlaying your own YAML per environment: Kustomize. They are not mutually exclusive - many pipelines use both.