kubernetes/kops · error

unknown output format: %q

Error message

unknown output format: %q

What it means

RunGetKeypairs validates options.Output against table, yaml, and json; any other value falls into the switch's default branch and returns "unknown output format: %q". Like the get_instances equivalent, it is strict input validation, and note the wording differs from get_instances ("unknown" vs "unsupported").

Source

Thrown at cmd/kops/get_keypairs.go:256

	case OutputYaml:
		y, err := yaml.Marshal(items)
		if err != nil {
			return fmt.Errorf("unable to marshal YAML: %v", err)
		}
		if _, err := out.Write(y); err != nil {
			return fmt.Errorf("error writing to output: %v", err)
		}
	case OutputJSON:
		j, err := json.Marshal(items)
		if err != nil {
			return fmt.Errorf("unable to marshal JSON: %v", err)
		}
		if _, err := out.Write(j); err != nil {
			return fmt.Errorf("error writing to output: %v", err)
		}

	default:
		return fmt.Errorf("unknown output format: %q", options.Output)
	}

	return nil
}

func completeGetKeypairs(ctx context.Context, f commandutils.Factory, options *GetKeypairsOptions, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
	commandutils.ConfigureKlogForCompletion()

	cluster, clientSet, completions, directive := GetClusterForCompletion(ctx, f, nil)
	if cluster == nil {
		return completions, directive
	}

	alreadySelected := sets.NewString(args...).Insert("all")
	_, _, completions, directive = completeKeyset(ctx, cluster, clientSet, nil, func(name string, keyset *fi.Keyset) bool {
		return !alreadySelected.Has(name)
	})

View on GitHub (pinned to 4c8573c808)

Solutions

1. Use one of: `kops get keypairs -o table|yaml|json`.
2. Ensure the format variable in scripts is non-empty and lowercase.
3. Check `kops get keypairs --help` for accepted -o values.
4. If you need another format, post-process the JSON/yaml output with jq/yq instead.

Example fix

// before
FMT=""; kops get keypairs -o "$FMT"   # unknown output format: ""
// after
FMT="json"; kops get keypairs -o "$FMT"

FMT="${OUTPUT:-json}"
case "$FMT" in
  table|yaml|json) ;;
  *) echo "invalid output '$FMT'; use table|yaml|json" >&2; exit 2 ;;
esac
kops get keypairs -o "$FMT"

if err := runKops("get", "keypairs", "-o", format); err != nil {
	if strings.Contains(err.Error(), "unknown output format") {
		return fmt.Errorf("%q rejected: must be table, yaml, or json", format)
	}
	return err
}

When it happens

Trigger: `kops get keypairs -o xml`, `-o`, `-o wide`, or an uppercase/mixed-case value; the empty default if a wrapper script passes an uninitialized OUTPUT variable.

Common situations: Script variables left empty (`-o "$FMT"` with FMT unset); copying flags from other tools (kubectl's `-o wide` does not exist here); case sensitivity assumptions (YAML vs yaml).

Understand the failure class

Background: "unknown output mode", "invalid value for flag", "expects true/false": fixing invalid flag value errors in CLI tools — this error's family across 24 libraries.

Related errors

• unsupported output format: %q
• unsupported output type %q
• --name is required
• cannot specify --cert with "all"
• cannot use both --admin and --user

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/e77c9edf5b2295b1. Report an issue: GitHub.