kubernetes/kops · error

unsupported output type %q

Error message

unsupported output type %q

What it means

In DryRun mode the switch over c.Output only accepts yaml and json; any other --output value falls into the default branch and returns this error immediately. It is a user input validation error, not a runtime failure.

Source

Thrown at cmd/kops/create_cluster.go:820

		}

		for _, o := range addons {
			obj = append(obj, o.ToUnstructured())
		}

		switch c.Output {
		case OutputYaml:
			if err := fullOutputYAML(out, obj...); err != nil {
				return fmt.Errorf("error writing cluster yaml to stdout: %v", err)
			}
			return nil
		case OutputJSON:
			if err := fullOutputJSON(out, true, obj...); err != nil {
				return fmt.Errorf("error writing cluster json to stdout: %v", err)
			}
			return nil
		default:
			return fmt.Errorf("unsupported output type %q", c.Output)
		}
	}

	// Note we perform as much validation as we can, before writing a bad config
	err = registry.CreateClusterConfig(ctx, clientset, cluster, instanceGroups, addons)
	if err != nil {
		return fmt.Errorf("error writing updated configuration: %v", err)
	}

	if len(c.SSHPublicKeys) == 0 {
		autoloadSSHPublicKeys := true
		switch c.CloudProvider {
		case "gce", "aws":
			autoloadSSHPublicKeys = false
		}

		if autoloadSSHPublicKeys {
			// Load from default locations, if found

View on GitHub (pinned to 4c8573c808)

Solutions

1. Use --output yaml or --output json exactly (lowercase).
2. Omit --dry-run if you want the default behavior instead of serialized output.
3. Check `kops create cluster --help` for supported output values.

Example fix

// before
kops create cluster ... --dry-run --output yml
// after
kops create cluster ... --dry-run --output yaml

output := strings.ToLower(c.Output)
if output != "yaml" && output != "json" {
	return fmt.Errorf("--output must be yaml or json, got %q", c.Output)
}

func isValidOutputFormat(s string) bool {
	return s == "yaml" || s == "json"
}

When it happens

Trigger: `kops create cluster --dry-run --output <something-other-than-yaml|json>`, e.g. --output yml, --output text, or --output Yaml (matching is case-sensitive).

Common situations: Typo (yml vs yaml); assuming other kops commands' output formats (e.g. table) apply here; passing an env-expanded empty string as --output.

Related errors

• unable to execute --dry-run without setting --output
• error writing cluster yaml to stdout: %v
• error writing cluster json to stdout: %v
• --project cannot be empty; specify a project or omit the fla
• cannot specify --key with "all"

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/d3970031be1665f6. Report an issue: GitHub.