kubernetes/kops · error

error parsing NonMasqueradeCIDR %q: %v

Error message

error parsing NonMasqueradeCIDR %q: %v

What it means

The cluster's networking.nonMasqueradeCIDR is set but is not a valid CIDR, so dependent subnets cannot be auto-assigned. net.ParseCIDR rejected the string; the value must be a proper network prefix like 100.64.0.0/10.

Source

Thrown at upup/pkg/fi/cloudup/populate_cluster_spec.go:368

	// completed.Topology.Bastion = c.InputCluster.Spec.Topology.Bastion

	if errs := validation.ValidateCluster(completed, true, clientset.VFSContext()); len(errs) != 0 {
		return fmt.Errorf("completed cluster failed validation: %v", errs.ToAggregate())
	}

	c.fullCluster = completed
	return nil
}

func (c *populateClusterSpec) assignSubnets(cluster *kopsapi.Cluster) error {
	if cluster.Spec.Networking.NonMasqueradeCIDR == "" {
		klog.Warningf("NonMasqueradeCIDR not set; can't auto-assign dependent subnets")
		return nil
	}

	_, nonMasqueradeCIDR, err := net.ParseCIDR(cluster.Spec.Networking.NonMasqueradeCIDR)
	if err != nil {
		return fmt.Errorf("error parsing NonMasqueradeCIDR %q: %v", cluster.Spec.Networking.NonMasqueradeCIDR, err)
	}
	nmOnes, nmBits := nonMasqueradeCIDR.Mask.Size()

	if cluster.Spec.KubeControllerManager == nil {
		cluster.Spec.KubeControllerManager = &kopsapi.KubeControllerManagerConfig{}
	}

	if cluster.Spec.Networking.PodCIDR == "" && nmBits == 32 {
		// Allocate as big a range as possible: the NonMasqueradeCIDR mask + 1, with a '1' in the extra bit
		ip := nonMasqueradeCIDR.IP.Mask(nonMasqueradeCIDR.Mask)
		ip[nmOnes/8] |= 128 >> (nmOnes % 8)
		cidr := net.IPNet{IP: ip, Mask: net.CIDRMask(nmOnes+1, nmBits)}
		cluster.Spec.Networking.PodCIDR = cidr.String()
		klog.V(2).Infof("Defaulted PodCIDR to %v", cluster.Spec.Networking.PodCIDR)
	}

	if cluster.Spec.Networking.ServiceClusterIPRange == "" {
		if nmBits > 32 {

View on GitHub (pinned to 4c8573c808)

Solutions

1. Correct nonMasqueradeCIDR to a valid CIDR notation (e.g. 100.64.0.0/10)
2. Re-run cluster spec population

When it happens

Trigger: Thrown at upup/pkg/fi/cloudup/populate_cluster_spec.go:368 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/ec87c0e77bb99c1c. Report an issue: GitHub.