kubernetes/kops · error

linode subnet %q requires a CIDR

Error message

linode subnet %q requires a CIDR

What it means

Linode NetworkModelBuilder.Build() validates that every subnet defines a CIDR block, which is required to create the Linode VPC subnet. An empty subnet.CIDR fails validation with this error, reported under the subnet's name.

Source

Thrown at pkg/model/linodemodel/network.go:55

		return fmt.Errorf("linode VPC requires at least one subnet")
	}

	seenSubnetNames := map[string]string{}
	region := ""
	for i, subnet := range b.Cluster.Spec.Networking.Subnets {
		subnetName := subnet.Name
		if subnetName == "" {
			subnetName = fmt.Sprintf("subnet %d", i)
		}

		if subnet.Name == "" {
			return fmt.Errorf("linode subnet %q requires a name", subnetName)
		}
		if subnet.Region == "" {
			return fmt.Errorf("linode subnet %q requires a region", subnetName)
		}
		if subnet.CIDR == "" {
			return fmt.Errorf("linode subnet %q requires a CIDR", subnetName)
		}

		normalizedSubnetName := linode.NormalizeLinodeLabel(b.ClusterName() + "-" + subnet.Name)
		if previousSubnetName, found := seenSubnetNames[normalizedSubnetName]; found {
			return fmt.Errorf("linode subnets %q and %q normalize to the same label %q", previousSubnetName, subnetName, normalizedSubnetName)
		}
		seenSubnetNames[normalizedSubnetName] = subnetName

		if region == "" {
			region = subnet.Region
			continue
		}
		if subnet.Region != region {
			return fmt.Errorf("linode subnets must all use the same region; found %q and %q", region, subnet.Region)
		}
	}

	name := linode.NormalizeLinodeLabel(b.ClusterName())

View on GitHub (pinned to 4c8573c808)

Solutions

1. Set cidr on each subnet in cluster.spec.networking.subnets (e.g. 10.0.0.0/24).
2. Verify the YAML key is cidr per the kops v1alpha2/v1beta1 API, not cidrBlock.
3. Ensure the CIDR does not overlap other subnets in the cluster VPC.
4. Re-run kops update cluster after fixing.

Example fix

// before
- name: us-east-1a
  region: us-east
// after
- name: us-east-1a
  region: us-east
  cidr: 10.0.0.0/24

for _, s := range cluster.Spec.Networking.Subnets {
    if s.CIDR == "" {
        return fmt.Errorf("subnet %q missing cidr", s.Name)
    }
    if _, _, err := net.ParseCIDR(s.CIDR); err != nil {
        return fmt.Errorf("subnet %q has invalid cidr %q", s.Name, s.CIDR)
    }
}

When it happens

Trigger: A cluster.spec.networking.subnets entry with name and region set but cidr omitted, empty, or under a wrong key (e.g. cidrBlock instead of cidr).

Common situations: Manifests copied from providers with different CIDR field names; templating leaving the cidr variable unsubstituted; hand-edited specs where the CIDR line was deleted.

Related errors

• linode VPC requires at least one subnet
• linode subnet %q requires a name
• linode subnet %q requires a region
• Subnet.VPC is required
• Subnet.VPC.ID is required

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/67dc9c9760906c3d. Report an issue: GitHub.