KubernetesHow-ToBeginner · 4 min read

How to Customize Helm Chart Values for Kubernetes Deployments

You can customize Helm chart values by using the --set flag to override specific values directly in the command line or by creating a values.yaml file with your custom settings and passing it with -f during installation or upgrade. This lets you change configurations without modifying the original chart.

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Syntax

The basic syntax to customize Helm chart values includes two main methods:

helm install my-release chart-name --set key=value overrides a single value.
helm install my-release chart-name -f custom-values.yaml uses a file with multiple custom values.

The --set flag is for quick, small changes, while -f is better for complex or many customizations.

bash

helm install my-release chart-name --set key=value
helm install my-release chart-name -f custom-values.yaml

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Example

This example shows how to customize the nginx Helm chart by setting the replica count and service type using both --set and a values.yaml file.

bash

# Create a custom values file named custom-values.yaml
replicaCount: 3
service:
  type: LoadBalancer

# Install nginx chart with custom values file
helm install my-nginx bitnami/nginx -f custom-values.yaml

# Or override values directly
helm install my-nginx bitnami/nginx --set replicaCount=3 --set service.type=LoadBalancer

Output

NAME: my-nginx LAST DEPLOYED: <timestamp> NAMESPACE: default STATUS: deployed REVISION: 1 TEST SUITE: None

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Common Pitfalls

Common mistakes when customizing Helm chart values include:

Using incorrect key names that don't match the chart's values.yaml structure.
Forgetting to quote values with special characters in --set.
Overriding nested values incorrectly without using dot notation.
Not validating the custom values file syntax, causing install failures.

Always check the chart's default values.yaml to know the correct keys and structure.

bash

# Wrong: missing dot notation for nested keys
helm install my-nginx bitnami/nginx --set service type=LoadBalancer

# Right: use dot notation
helm install my-nginx bitnami/nginx --set service.type=LoadBalancer

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Quick Reference

Command	Description
helm install my-release chart-name --set key=value	Override a single value directly in the command line
helm install my-release chart-name -f values.yaml	Use a custom values file for multiple settings
helm upgrade my-release chart-name -f values.yaml	Update an existing release with new values
helm get values my-release	View current values of a deployed release
helm template chart-name -f values.yaml	Render templates locally with custom values

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Key Takeaways

Use --set for quick, single value overrides and -f for complex or multiple customizations.

Always check the chart's default values.yaml to know correct keys and structure.

Use dot notation to override nested values correctly with --set.

Validate your custom values.yaml file syntax to avoid deployment errors.

You can update existing releases with customized values using helm upgrade.