kubernetes/kops · error

error writing to output: %v

Error message

error writing to output: %v

What it means

RunValidateCluster wraps the failure of writing marshaled YAML validation results to the command's output writer. It fires in the --output yaml branch when the underlying io.Writer (stdout/file) errors, e.g. a closed or broken pipe; the JSON branch has the analogous error.

Source

Thrown at cmd/kops/validate_cluster.go:216

				time.Sleep(options.interval)
				continue
			} else {
				return nil, fmt.Errorf("unexpected error during validation: %v", err)
			}
		}

		switch options.output {
		case OutputTable:
			if err := validateClusterOutputTable(result, cluster, instanceGroups, out); err != nil {
				return nil, err
			}
		case OutputYaml:
			y, err := yaml.Marshal(result)
			if err != nil {
				return nil, fmt.Errorf("unable to marshal YAML: %v", err)
			}
			if _, err := out.Write(y); err != nil {
				return nil, fmt.Errorf("error writing to output: %v", err)
			}
		case OutputJSON:
			j, err := json.Marshal(result)
			if err != nil {
				return nil, fmt.Errorf("unable to marshal JSON: %v", err)
			}
			if _, err := out.Write(j); err != nil {
				return nil, fmt.Errorf("error writing to output: %v", err)
			}
		default:
			return nil, fmt.Errorf("unknown output format: %q", options.output)
		}

		if len(result.Failures) == 0 {
			consecutive++
			if consecutive < options.count {
				klog.Infof("(will retry): cluster passed validation %d consecutive times", consecutive)
				if options.wait > 0 {

View on GitHub (pinned to 4c8573c808)

Solutions

1. Check that stdout is not closed or a redirected file is writable
2. Use table output as a fallback
3. Capture output to a file with proper permissions

When it happens

Trigger: Thrown at cmd/kops/validate_cluster.go:216 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/eef8c2186d69f267. Report an issue: GitHub.