kubernetes/kops · error

error hashing data: %v

Error message

error hashing data: %v

What it means

copyToHasher performs io.Copy from the source reader into the hasher and wraps any copy failure as 'error hashing data'. This is the inner I/O failure surfaced by HashAlgorithm.Hash (and indirectly HashFile) — the data stream could not be read to completion.

Source

Thrown at util/pkg/hashing/hash.go:152

	return &Hash{Algorithm: ha, HashValue: hasher.Sum(nil)}, nil
}

func (ha HashAlgorithm) HashFile(p string) (*Hash, error) {
	f, err := os.OpenFile(p, os.O_RDONLY, 0)
	if err != nil {
		if os.IsNotExist(err) {
			return nil, err
		}
		return nil, fmt.Errorf("error opening file %q: %v", p, err)
	}
	defer try.CloseFile(f)
	return ha.Hash(f)
}

func copyToHasher(dest io.Writer, src io.Reader) (int64, error) {
	n, err := io.Copy(dest, src)
	if err != nil {
		return n, fmt.Errorf("error hashing data: %v", err)
	}
	return n, nil
}

func (l *Hash) Equal(r *Hash) bool {
	return (l.Algorithm == r.Algorithm) && bytes.Equal(l.HashValue, r.HashValue)
}

View on GitHub (pinned to 4c8573c808)

Solutions

1. Retry the hashing operation; transient I/O errors often resolve
2. Check disk health and file availability at the source path/URL
3. Look at the wrapped cause (%v) for the concrete I/O error and address it directly
4. Stage data locally first, then hash the local copy to isolate download vs hashing failures

Example fix

// before
h, err := algo.Hash(remoteReader)
// after
tmp, err := os.CreateTemp("", "asset")
if err != nil { return err }
if _, err := io.Copy(tmp, remoteReader); err != nil { return fmt.Errorf("download: %w", err) }
tmp.Seek(0, 0)
h, err := algo.Hash(tmp)

null

null

h, err := algo.Hash(r)
if err != nil {
	if strings.Contains(err.Error(), "error hashing data") {
		return fmt.Errorf("source stream failed during hashing: %w; retry the operation", err)
	}
	return err
}

When it happens

Trigger: Any Hash/HashFile call where the underlying reader errors mid-copy: network interruption during asset download, disk read error, closed file descriptor, or a reader implementation returning an error.

Common situations: Unstable network while verifying remote asset hashes; reading from a file on a failing disk; readers that error on EOF handling; concurrent modification of the file being hashed.

Related errors

• error while hashing resource: %v
• error hashing manifest: %v
• error hashing manifest location: %v
• error writing to output: %v
• reading existing keyset: %v

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/92796bbfd0840222. Report an issue: GitHub.