kubernetes/kops · error

error doing HEAD on %q: %v

Error message

error doing HEAD on %q: %v

What it means

hashFromHTTPHeader performs an HTTP HEAD against an asset URL to discover its checksum; the request itself failed (DNS, connection refused, 404, proxy failure), so no hash can be obtained.

Source

Thrown at upup/pkg/fi/assetstore.go:184

		klog.Infof("    %s %s", match.Key, match.AssetPath)
	}
	return nil, fmt.Errorf("found multiple matching assets for key: %q", key)
}

// Add an asset into the store, in one of the recognized formats (see Assets in types package)
func (a *AssetStore) AddForTest(id string, path string, content string) {
	a.assets = append(a.assets, &asset{
		Key:       id,
		AssetPath: path,
		resource:  NewStringResource(content),
	})
}

func hashFromHTTPHeader(url string) (*hashing.Hash, error) {
	klog.Infof("Doing HTTP HEAD on %q", url)
	response, err := http.Head(url)
	if err != nil {
		return nil, fmt.Errorf("error doing HEAD on %q: %v", url, err)
	}
	defer response.Body.Close()

	etag := response.Header.Get("ETag")
	etag = strings.TrimSpace(etag)
	etag = strings.Trim(etag, "'\"")

	if etag != "" {
		if len(etag) == 32 {
			// Likely md5
			return hashing.HashAlgorithmMD5.FromString(etag)
		}
	}

	return nil, fmt.Errorf("unable to determine hash from HTTP HEAD: %q", url)
}

// Add an asset into the store, in one of the recognized formats (see Assets in types package)

View on GitHub (pinned to 4c8573c808)

Solutions

1. Verify the URL is reachable from the machine running kOps (curl -I)
2. Fix proxy/TLS settings if the environment blocks the request
3. Retry — transient network failures are a common cause

When it happens

Trigger: Thrown at upup/pkg/fi/assetstore.go:184 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/0ae4960bbd83e861. Report an issue: GitHub.