Key features
- Base-and-overlay model — template-free YAML patching for APAC multi-environment Kubernetes configuration
- Strategic merge patches — minimal overlay patches that change only the fields that differ per APAC environment
- JSON6902 patches — surgical YAML patches using RFC 6902 JSON Patch operations for APAC complex customisation
- Image transformer — single-location image tag management across all APAC overlay manifests
- ConfigMap/Secret generators — content-hashed config generation triggering automatic APAC pod restarts
- Component overlays — reusable configuration patches applied across multiple APAC environment overlays
- kubectl integration — built into kubectl as `kubectl apply -k` without separate tool installation
Best for
- APAC GitOps teams wanting pure-YAML Kubernetes configuration management without Helm template complexity
- Platform teams managing multi-environment APAC Kubernetes configurations (dev/staging/prod) with minimal divergence from a shared base
- Engineering teams using Flux or ArgoCD where Kustomize overlays are the GitOps deployment unit for APAC workloads
- APAC teams who value readability — Kustomize overlays are readable plain YAML that any engineer can understand without template knowledge
Limitations to know
- ! Kustomize lacks release management — there is no concept of Kustomize releases, upgrade history, or rollback; APAC teams need Git history and manual rollback procedures
- ! Kustomize has no dependency management — charts that depend on other charts require Helm or manual coordination for APAC application stack deployments
- ! Kustomize patches can become complex at scale — large APAC deployments with many overlays and patches become difficult to reason about without clear directory conventions
- ! Kustomize is not a templating engine — APAC applications requiring complex conditional logic (if/else, loops over complex data) need Helm, Jsonnet, or another templating approach
About Kustomize
Kustomize is an open-source Kubernetes configuration management tool, built into kubectl as `kubectl apply -k`, that provides APAC platform engineering teams with a template-free way to customise Kubernetes manifests for different APAC environments — using a base-and-overlay model where base manifests define the canonical resource configuration and environment-specific overlays apply targeted patches without introducing Go template syntax into YAML files.
Kustomize's overlay model — where a base directory contains the shared Kubernetes YAML (Deployment, Service, ConfigMap) and environment-specific overlay directories contain `kustomization.yaml` files that reference the base and apply patches (image tag updates, replica count changes, resource limit adjustments, namespace assignment) — enables APAC platform teams to manage multi-environment Kubernetes configuration through pure YAML without template rendering. APAC developers read the overlay manifests and immediately understand what the production environment differs from staging, without learning Go template syntax.
Kustomize's strategic merge patches — where an overlay patch YAML specifies only the fields to change relative to the base manifest, with Kustomize merging the patch into the base during `kubectl apply -k` — keep overlay patches minimal and readable. A production overlay that changes only the replica count and CPU limit is a 10-line patch file, not a full copy of the Deployment manifest.
Kustomize's image transformer — where `images:` in `kustomization.yaml` replaces image tags across all manifests in the overlay without individual manifest edits — enables APAC CI/CD pipelines to update the deployed image tag by editing a single field in the overlay's `kustomization.yaml`. GitOps tools like Flux's image automation controller and Argo CD Image Updater use this mechanism to automatically update APAC Kubernetes deployments when new image versions are pushed to APAC container registries.
Kustomize's ConfigMap and Secret generators — which generate Kubernetes ConfigMaps and Secrets from files and literals in `kustomization.yaml`, automatically appending a content hash to resource names — enable APAC applications to automatically trigger pod restarts when configuration changes, because the ConfigMap name changes (new hash) invalidate the volume mount reference, forcing a Kubernetes reconciliation that restarts affected pods.
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