kubernetes/kops · error

invalid base channel location: %q

Error message

invalid base channel location: %q

What it means

ResolveChannel turns a user-supplied channel location string into an absolute URL. If the location is not absolute, kOps parses its built-in DefaultChannelBase and resolves the relative location against it. This error means parsing the hard-coded DefaultChannelBase URL failed, which indicates an internal build/configuration corruption of the default channel constant rather than anything the caller passed.

Source

Thrown at pkg/apis/kops/channel.go:121

	KopsVersion string `json:"kopsVersion,omitempty"`
}

// ResolveChannel maps a channel to an absolute URL (possibly a VFS URL)
// If the channel is the well-known "none" value, we return (nil, nil)
func ResolveChannel(location string) (*url.URL, error) {
	if location == "none" {
		return nil, nil
	}

	u, err := url.Parse(location)
	if err != nil {
		return nil, fmt.Errorf("invalid channel location: %q", location)
	}

	if !u.IsAbs() {
		base, err := url.Parse(DefaultChannelBase)
		if err != nil {
			return nil, fmt.Errorf("invalid base channel location: %q", DefaultChannelBase)
		}
		klog.V(4).Infof("resolving %q against default channel location %q", location, DefaultChannelBase)
		u = base.ResolveReference(u)
	}

	return u, nil
}

// LoadChannel loads a Channel object from the specified VFS location
func LoadChannel(vfsContext *vfs.VFSContext, location string) (*Channel, error) {
	resolvedURL, err := ResolveChannel(location)
	if err != nil {
		return nil, err
	}

	if resolvedURL == nil {
		return &Channel{}, nil
	}

View on GitHub (pinned to 4c8573c808)

Solutions

1. Check the compiled-in value of DefaultChannelBase in pkg/apis/kops/channel.go and correct any typo (must be a valid absolute URL with scheme).
2. Rebuild kOps from unmodified upstream source (make kops) to rule out a corrupted or patched binary.
3. As a workaround, pass a fully absolute channel URL (e.g. https://raw.githubusercontent.com/kubernetes/kops/master/channels/stable) so the base-parsing branch is never taken.

Example fix

// before (bad build-time override)
DefaultChannelBase = "https//kops.s3.amazonaws.com/channels"
// after
DefaultChannelBase = "https://kops.s3.amazonaws.com/channels"

u, err := url.Parse(location)
if err != nil { return err }
if !u.IsAbs() {
    if _, err := url.Parse(kops.DefaultChannelBase); err != nil {
        return fmt.Errorf("kops build has invalid DefaultChannelBase: %w", err)
    }
}

func isAbsoluteURL(s string) bool { u, err := url.Parse(s); return err == nil && u.IsAbs() }

u, err := kops.ResolveChannel(location)
if err != nil {
    if strings.Contains(err.Error(), "invalid base channel location") {
        // fall back to absolute channel URL
        u, err = kops.ResolveChannel(defaultChannelURLAbsolute)
    }
    return err
}

When it happens

Trigger: Calling LoadChannel or ResolveChannel with a relative channel location (e.g. "stable") when url.Parse(DefaultChannelBase) returns an error — practically only when the compiled-in DefaultChannelBase constant is malformed or overridden by a bad build/link-time replacement.

Common situations: Custom kOps builds that rewrite DefaultChannelBase to an invalid URL; corrupted source vendoring; automated tooling that patches the constant with a typo (e.g. missing scheme like "https/channels.example.com").

Related errors

• invalid channel location: %q
• unable to parse CNI plugin binaries asset URL %q: %v
• error loading channel %q: %v
• error reading channel %q: %v
• error parsing channel %q: %v

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/0c7eb436b65b4812. Report an issue: GitHub.