Why I Prefer Custom Helm Charts Over Vendor-Supplied Ones

As a DevOps architect who has designed, deployed, and maintained Kubernetes workloads across a wide range of environments, I've come to a firm conclusion: vendor-supplied or generic Helm charts are a great starting point — but they should never be the final destination. In most real-world scenarios, custom application-specific Helm charts provide far more maintainability, control, and long-term security.

Let me explain why, with examples from the trenches.

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1. Generic Helm Charts Are a Black Box of Complexity

Popular open-source Helm charts — like those from the Bitnami or the Helm community repositories — often cater to a wide audience. While this is great for coverage, it also means you're pulling in hundreds of lines of values.yaml configurations, conditionals, and templating logic to cover use cases you may never need.

Take the Bitnami Kafka Helm chart as an example. It supports:

• Kubernetes and OpenShift
• Multiple Zookeeper modes
• External vs. internal access configs
• Complex affinity and autoscaling
• TLS, SASL, RBAC, metrics, sidecars…

It’s powerful, no doubt — but if you want to make a small change (like configuring only certain environment variables on certain pods), you’ll be diving into values files, reading template logic, and often forking the chart anyway.

In contrast, a custom chart does only what you need. It becomes your golden, readable, testable deployment definition.

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2. Security Risks Hide in Overgeneralized Defaults

Generic charts often prioritize "getting things running" over production readiness. For example:

• Many charts enable admin interfaces (like the Kafka JMX port or ArgoCD admin password) by default with no authentication.
• Charts like Apache Airflow or Harbor have historically shipped with exposed secrets or disabled TLS.
• CVEs have been filed against Helm charts that mount writable hostPaths or use privileged containers — all for the sake of compatibility.

When you write a chart yourself, you remove all unused code paths, lock down privileges, and review every volume mount and port exposure.

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3. Operational Burden Increases Over Time

One of the biggest myths about vendor-supplied charts is that they reduce operational overhead. At first, maybe. But fast-forward 6 months:

• You need to upgrade the app.
• The vendor chart changed structure.
• Your custom values.yaml is now incompatible.
• Your production outages start with “Helm upgrade failed…”

You then face a choice:

• Fork the chart and maintain it forever.
• Rewrite your values and re-test everything.

Had you written a custom chart tailored to your application from day one, upgrades would have been surgical — and under your control.

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4. Custom Charts Align With CI/CD, GitOps, and Developer Expectations

DevOps today isn’t just about deploying infra — it’s about enabling teams. A custom Helm chart:

• Can follow your GitOps model and directory structure.
• Can expose only the settings developers actually need in values.yaml.
• Can integrate seamlessly with your CI pipelines (e.g., test snapshots, render diffs, preview environments).
• Avoids the cognitive load of “What does this Helm chart actually do?”

In one project, we replaced the official Helm chart of Keycloak with a stripped-down custom chart. We saw:

• Reduced upgrade times (minutes to seconds).
• Fewer surprise regressions.
• Clear boundaries between infrastructure and app configuration.

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5. You’ll Write a Custom Chart Eventually — Might As Well Start That Way

Most teams using vendor charts eventually:

• Fork the chart to make a tweak.
• Maintain a local copy.
• Patch it with scripts because upstream won’t accept their use case.

At that point, you’re essentially maintaining a chart you didn’t write and don’t fully understand. Why not write a smaller, simpler, tailored chart from scratch? One that:

• Fits your naming conventions.
• Works with your monitoring/logging stack.
• Encodes your security policies directly.

It doesn’t have to be 100% from scratch — pull in snippets and patterns from upstream, but make it yours.

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Final Thoughts

Vendor Helm charts offer convenience, but they are general-purpose tools in a world that increasingly demands application-specific precision. Kubernetes gives you the power to control every detail of your application’s lifecycle — don’t surrender that power to a templating engine you can barely debug.

Instead, take the time to understand your deployment, encode it as a custom Helm chart, and build confidence in what actually runs in your cluster.

The best Helm chart is the one you wrote, understand, and trust.