kubernetes/kops · error

error executing template %q: %w

Error message

error executing template %q: %w

What it means

After successfully parsing, RenderTemplate executes the template against cluster.spec. This error wraps any runtime execution failure — nil map index issues aside (missingkey=zero), these are typically data/type errors such as calling a template function with wrong arguments or ranging over a non-iterable value.

Source

Thrown at upup/pkg/fi/cloudup/template_functions.go:133

	tf := r.newTemplateFunctions(tasks)
	funcMap := template.FuncMap{}
	if err := tf.AddTo(funcMap, r.secretStore); err != nil {
		return nil, err
	}
	if tasks == nil {
		funcMap["Task"] = func(typeName, name string) (fi.CloudupTask, error) { return nil, nil }
		funcMap["HasTask"] = func(typeName, name string) bool { return false }
		funcMap["TasksByType"] = func(typeName string) ([]fi.CloudupTask, error) { return nil, nil }
	}

	t := template.New(name).Funcs(funcMap).Option("missingkey=zero")
	if _, err := t.Parse(string(source)); err != nil {
		return nil, fmt.Errorf("error parsing template %q: %w", name, err)
	}

	var buf bytes.Buffer
	if err := t.ExecuteTemplate(&buf, name, r.modelContext.Cluster.Spec); err != nil {
		return nil, fmt.Errorf("error executing template %q: %w", name, err)
	}
	return buf.Bytes(), nil
}

// CloudControllerConfigArgv returns the cloud controller argv without binding any task graph.
func (r *addonTemplateRenderer) CloudControllerConfigArgv() ([]string, error) {
	return r.newTemplateFunctions(nil).CloudControllerConfigArgv()
}

// AddTo defines the available functions we can use in our YAML models.
// If we are trying to get a new function implemented it MUST
// be defined here.
func (tf *TemplateFunctions) AddTo(dest template.FuncMap, secretStore fi.SecretStore) (err error) {
	cluster := tf.Cluster

	dest["ToJSON"] = tf.ToJSON
	dest["ToYAML"] = tf.ToYAML
	dest["KubeObjectToApplyYAML"] = kubemanifest.KubeObjectToApplyYAML

View on GitHub (pinned to 4c8573c808)

Solutions

1. Read the wrapped inner error to find the failing template line and fix the expression or function call
2. Check the template functions available in your kOps version (template_functions.go) and update calls to match
3. Test-render with the same cluster spec via `kops toolbox template` if available to iterate quickly

Example fix

// before
region: {{ Region }}
// after
region: {{ Region . }}

// render against real ClusterSpec in a unit test before deploy
tmpl := template.New(name).Funcs(funcMap).Option("missingkey=zero")
if err := tmpl.Execute(io.Discard, cluster.Spec); err != nil {
	t.Fatalf("template %s fails at runtime: %v", name, err)
}

out, err := r.RenderTemplate(name, source)
if err != nil && strings.Contains(err.Error(), "error executing template") {
	// inspect wrapped error for the failing line/function
	return fmt.Errorf("rendering %s: %w", name, err)
}

When it happens

Trigger: Template parses but fails at ExecuteTemplate: calling a template function with wrong argument types (e.g. AddInt on a non-integer), indexing a field that doesn't exist on ClusterSpec in this kOps version, or a custom func returning an error.

Common situations: Templates written for a different kOps version referencing removed ClusterSpec fields or renamed template functions; custom addons calling helpers with wrong signatures.

Related errors

• error parsing template %q: %w
• template tasks are not available during this render phase
• listing SSH key tasks: %w
• error creating kops config template: %w
• error creating gcp machine template: %w

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/85324e6a01e17522. Report an issue: GitHub.