kubernetes/kops · error

CIDR cannot specified for networks where mode=%s

Error message

CIDR cannot specified for networks where mode=%s

What it means

Validation error from Network.CheckChanges. A CIDR is set on the network spec while Mode is not 'legacy' (auto/custom modes have GCE-managed or subnet-scoped ranges), so the contradictory combination is rejected before any API call.

Source

Thrown at upup/pkg/fi/cloudup/gcetasks/network.go:117

	}
	return u.BuildURL()
}

func (e *Network) Run(c *fi.CloudupContext) error {
	return fi.CloudupDefaultDeltaRunMethod(e, c)
}

func (_ *Network) CheckChanges(a, e, changes *Network) error {
	cidr := fi.ValueOf(e.CIDR)
	switch e.Mode {
	case "legacy":
		if cidr == "" {
			return fmt.Errorf("CIDR must specified for networks where mode=legacy")
		}
		klog.Warningf("using legacy mode for GCE network %q", fi.ValueOf(e.Name))
	default:
		if cidr != "" {
			return fmt.Errorf("CIDR cannot specified for networks where mode=%s", e.Mode)
		}
	}

	switch e.Mode {
	case "auto":
	case "custom":
	case "legacy":
		// Known

	case "":
		// Treated as "keep existing", only allowed for shared mode
		if !fi.ValueOf(e.Shared) {
			return fmt.Errorf("must specify mode for (non-shared) Network")
		}

	default:
		return fmt.Errorf("unknown mode %q for Network", e.Mode)
	}

View on GitHub (pinned to 4c8573c808)

Solutions

1. Remove the CIDR from the network spec for auto/custom mode networks
2. Or set mode=legacy if a network-level IPv4 range is truly intended

When it happens

Trigger: Thrown at upup/pkg/fi/cloudup/gcetasks/network.go:117 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/63abf288d37b9f1f. Report an issue: GitHub.