Why I Stopped Fighting With Helm and Learned to Love Kustomize

I was a Helm believer. Charts, values files, the whole ecosystem - I thought it was the way to manage Kubernetes manifests. Then one day, a single misplaced curly brace made me question everything.

💥 The Breaking Point

It was a Friday afternoon (because when else do things break?). I was updating our production Helm chart to add a new environment variable. Simple task, right? Just add one line to the values.yaml and update the template.

env:
{{- range $key, $value := .Values.env }}
  - name: {{ $key }}
    value: {{ $value | quote }}
{{- end }}
{{- if .Values.extraEnv }}
{{ toYaml .Values.extraEnv | indent 2 }}  # <- The indent was wrong
{{- end }}

One wrong indent. That's all it took. The deployment went out, pods started crashing, and I spent the next 3 hours debugging YAML templating instead of actual infrastructure problems.

🤔 What Was Wrong With Helm

Don't get me wrong - Helm is powerful. But with power comes complexity:

• Templating syntax is confusing - Go templates inside YAML? My brain hurts.
• Debugging is painful - helm template --debug only gets you so far
• Values inheritance is complex - Multiple values files can lead to unexpected overrides
• The rendered output is hard to review - What actually gets applied?

✨ Discovering Kustomize

Kustomize takes a different approach: instead of templating, it uses overlays and patches. Your base manifests are plain YAML - no templates, no special syntax. Then you layer modifications on top.

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

resources:
  - deployment.yaml
  - service.yaml

namePrefix: prod-

patches:
  - patch: |-
      - op: replace
        path: /spec/replicas
        value: 3
    target:
      kind: Deployment

The beauty? Every file is valid YAML. You can kubectl apply the base directly. You can see exactly what changes each overlay makes.

🔄 The Migration

Migrating wasn't instant, but it was straightforward:

1. Run helm template to get the rendered manifests
2. Split them into logical base files
3. Create overlays for each environment
4. Test with kustomize build

⚖️ The Verdict

After 6 months with Kustomize, here's my take:

Would I go back to Helm? For complex third-party charts, maybe. For my own applications? Kustomize all the way.

What's your experience with Helm vs Kustomize? Share your thoughts!