kubernetes/kops · error

encoding resources for %v: %w

Error message

encoding resources for %v: %w

What it means

This error wraps a failed os.File.Write when kops writes a serialized resource dump (JSON or YAML) to a file in the artifacts directory during a cluster dump. It is thrown by dumpGVRNamespaces after the resource list has been marshaled successfully but the bytes could not be written to disk. The wrapped %w error carries the underlying filesystem failure (disk full, permissions, closed file, I/O error).

Source

Thrown at pkg/dump/resourcedumper.go:259

				err: fmt.Errorf("marshaling to json for %v: %w", job, err),
			}
			continue
		}

		switch d.output {
		case "yaml":
			contents, err = yaml.JSONToYAML(contents)
			if err != nil {
				results <- resourceDumpResult{
					err: fmt.Errorf("marshaling to yaml for %v: %w", job, err),
				}
				continue
			}
		}
		_, err = resFile.Write(contents)
		if err != nil {
			results <- resourceDumpResult{
				err: fmt.Errorf("encoding resources for %v: %w", job, err),
			}
			continue
		}
		results <- resourceDumpResult{}
	}
}

func maskObject(obj runtime.Object) error {
	if obj.GetObjectKind().GroupVersionKind() == (schema.GroupVersionKind{Group: "", Version: "v1", Kind: "Secret"}) {
		unstructuredObj, err := runtime.DefaultUnstructuredConverter.ToUnstructured(obj)
		if err != nil {
			return err
		}
		data, ok, err := unstructured.NestedMap(unstructuredObj, "data")
		if err != nil {
			return fmt.Errorf("getting data from secret: %w", err)
		}
		if ok {

View on GitHub (pinned to 4c8573c808)

Solutions

1. Check free disk space on the filesystem holding the artifacts directory (df -h) and free space or redirect the dump to a volume with room for the full dump.
2. Verify the process user has write permission on the artifacts directory (ls -ld <artifactsDir>) and rerun with corrected permissions or a different directory.
3. Confirm the artifacts volume is mounted and stable for the duration of the dump; re-run the dump after remounting.
4. Inspect the wrapped error (the %w cause) with errors.Unwrap or %v of the returned error for the exact syscall failure (ENOSPC, EACCES, EIO) and address it accordingly.

Example fix

// before: writing dump contents without checking for partial writes or syncing
_, err = resFile.Write(contents)
if err != nil {
    results <- resourceDumpResult{err: fmt.Errorf("encoding resources for %v: %w", job, err)}
}
// after: pre-check disk capacity / log the wrapped cause to diagnose ENOSPC quickly
if stat, statErr := os.Stat(path.Dir(resPath)); statErr != nil || stat == nil {
    klog.Warningf("artifacts dir %q unavailable before write: %v", path.Dir(resPath), statErr)
}
if _, err = resFile.Write(contents); err != nil {
    results <- resourceDumpResult{err: fmt.Errorf("encoding resources for %v: %w", job, err)}
}

// before dumping, ensure the artifacts dir is writable and has headroom
info, err := os.Stat(artifactsDir)
if err != nil || !info.IsDir() {
    return fmt.Errorf("artifacts dir %q missing: %w", artifactsDir, err)
}
probe, err := os.CreateTemp(artifactsDir, ".writecheck")
if err != nil {
    return fmt.Errorf("artifacts dir %q not writable: %w", artifactsDir, err)
}
probe.Close()
os.Remove(probe.Name())

// each resourceDumpResult carries an error; collect and inspect the wrapped cause
for r := range results {
    if r.err != nil {
        var pathErr *fs.PathError
        if errors.As(r.err, &pathErr) {
            klog.Errorf("dump write failed on %s: %v (op=%s, path=%s)", pathErr.Err, pathErr.Op, pathErr.Path)
        } else {
            klog.Errorf("dump failed: %v", r.err)
        }
    }
}

When it happens

Trigger: The worker goroutine in dumpGVRNamespaces has created resFile via os.Create and, after marshaling the resource list (and optionally converting to YAML), resFile.Write(contents) returns a non-nil error. Causes include a full disk, the artifacts directory/file being removed mid-dump, insufficient write permissions, or an EIO on the backing volume.

Common situations: Running `kops get -o yaml --full` or `kops toolbox dump` on a node with a full disk; dumping to an artifactsDir on a volume that gets unmounted during the dump; running kops as a user without write permission to the artifacts directory; large cluster dumps exhausting disk space mid-write.

Related errors

• creating directory %q: %w
• creating file %q: %w
• error reading user provided private key %q: %v
• reading encryption config %v: %v
• error reading SSH public key %v: %v

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/6bd36c8018b346c0. Report an issue: GitHub.