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Component overrides let you customize a single install’s Helm values or Terraform variables without touching your app config. They’re defined per-install, so one customer can get a different chart configuration or a different set of Terraform variables while every other install keeps the app defaults. Use them for one-off customizations that don’t belong in your app config, such as bumping a replica count for a customer under load, pinning a region for a specific install, or applying a temporary support tweak, where authoring a new input or editing the shared component would be overkill.
Overrides are configured on the install, not the component. The component’s app config stays the source of truth for every other install.

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Configuring overrides

Overrides live in the install config under a [components.<name>] block, keyed by the component’s name. Each component supports exactly one override field, matching its type:
Component typeFieldFormatBehavior
Helm charthelm_valuesYAMLDeep-merges over the component’s app-config values; wins on overlapping keys.
Terraform moduletf_vars.tfvars (HCL/JSON)Appended as the final, highest-precedence -var-file.

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Helm values

helm_values is a raw YAML string that deep-merges over the Helm component’s app-config values. Overlapping keys win, and keys you don’t mention are left untouched.
install.toml
name = "customer-acme"

[components.clickhouse]
helm_values = """
replicas: 3
resources:
  limits:
    memory: 4Gi
"""

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Terraform variables

tf_vars is a raw .tfvars string (HCL or JSON) appended as the final -var-file at deploy time, so it wins over the component’s vars map and any var_files. The variables must already be declared in the module.
install.toml
name = "customer-acme"

[components.vpc]
tf_vars = """
cidr = "10.0.0.0/16"
"""
You can set overrides for multiple components in the same install config:
install.toml
name = "customer-acme"

[components.vpc]
tf_vars = """
cidr = "10.0.0.0/16"
"""

[components.clickhouse]
helm_values = """
replicas: 3
"""

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Precedence

Overrides are the highest-precedence layer. For Helm, they deep-merge on top of the app-config values and win on any key they set. For Terraform, they’re applied as the last -var-file, so they win over the module’s vars and var_files.

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Applying overrides

Overrides are applied by syncing the install config with the CLI: 
nuon installs sync --file install.toml --app-id <your-app-id> --yes
The CLI validates override syntax locally before making any API calls: helm_values must be valid YAML and tf_vars must be valid HCL. Because an override changes a component’s deploy config, syncing it triggers a redeploy of the affected component.

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Clearing an override

To revert a component to its app-config values, remove its [components.<name>] block (or the individual field) from the install config and sync again. The next sync clears the override and redeploys the component with the app defaults.