kubernetes/kops · warning

KubernetesPath::Hash not supported

Error message

KubernetesPath::Hash not supported

What it means

KubernetesPath represents a path inside the k8s API (e.g. via a ConfigMap-backed VFS), which stores opaque string objects. The VFS layer cannot compute a content hash for such paths, so Hash() unconditionally returns this error for every hash algorithm.

Source

Thrown at util/pkg/vfs/k8sfs.go:133

func (p *KubernetesPath) ReadDir() ([]Path, error) {
	return nil, fmt.Errorf("KubernetesPath::ReadDir not supported")
}

func (p *KubernetesPath) ReadTree(ctx context.Context) ([]Path, error) {
	return nil, fmt.Errorf("KubernetesPath::ReadTree not supported")
}

func (p *KubernetesPath) Base() string {
	return path.Base(p.key)
}

func (p *KubernetesPath) PreferredHash() (*hashing.Hash, error) {
	return p.Hash(hashing.HashAlgorithmMD5)
}

func (p *KubernetesPath) Hash(a hashing.HashAlgorithm) (*hashing.Hash, error) {
	return nil, fmt.Errorf("KubernetesPath::Hash not supported")
}

View on GitHub (pinned to 4c8573c808)

Solutions

1. Avoid hashing KubernetesPath objects; check the concrete path type before calling Hash/PreferredHash and skip or handle unsupported backends
2. If you need content identity for k8s-backed data, read the file contents (ReadFile) and hash the bytes yourself
3. Report/fix upstream: implement Hash or change PreferredHash to return a sentinel like vfs.ErrHashNotSupported so callers can branch

Example fix

// before
h, err := path.PreferredHash() // fails for k8s-backed paths
// after
if _, ok := path.(*vfs.KubernetesPath); ok {
    data, err := path.ReadFile(ctx)
    h := hashing.HashAlgorithmMD5.Hash(data)
} else {
    h, err = path.PreferredHash()
}

func canHash(p vfs.Path) bool { _, ok := p.(*vfs.KubernetesPath); return !ok }

func isKubernetesPath(p vfs.Path) (*vfs.KubernetesPath, bool) { kp, ok := p.(*vfs.KubernetesPath); return kp, ok }

h, err := p.PreferredHash()
if err != nil {
    if _, ok := p.(*vfs.KubernetesPath); ok { /* fall back to hashing ReadFile bytes */ }
    return err
}

When it happens

Trigger: Any call to KubernetesPath.Hash() — including the common indirect path where vfs path hashing is requested via PreferredHash(), which delegates to Hash(hashing.HashAlgorithmMD5).

Common situations: Code that hashes paths generically (e.g. comparing cluster spec files, caching by content hash) when the vfs path happens to be backed by the Kubernetes API server rather than S3/GCS/local storage.

Related errors

• method ConfigBaseFor not supported in server-side client
• server-side client does not support MirrorTo
• invalid kubernetes vfs path: %q
• ReadOnlyError
• error adding needs-update label: %v

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/cbb9d96d8cec6916. Report an issue: GitHub.