kubernetes/kops · error

GCE networks in legacy mode are not supported. Please conve

Error message

GCE networks in legacy mode are not supported.  Please convert to auto mode or specify a different network.

What it means

Hard stop from Network.RenderGCE when an existing network (a != nil) is in legacy mode. Legacy networks lack subnetworks, which kOps requires; the task explicitly refuses to proceed and directs the user to convert the network or choose another one.

Source

Thrown at upup/pkg/fi/cloudup/gcetasks/network.go:184

			// is serialized, which results in the network being created with
			// the auto-create subnetworks default of "true". Explicitly send
			// the default value.
			network.ForceSendFields = []string{"AutoCreateSubnetworks"}

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

		op, err := t.Cloud.Compute().Networks().Insert(t.Cloud.Project(), network)
		if err != nil {
			return fmt.Errorf("error creating Network: %v", err)
		}
		if err := t.Cloud.WaitForOp(op); err != nil {
			return fmt.Errorf("error waiting for Network creation to complete: %w", err)
		}
	} else {
		if a.Mode == "legacy" {
			return fmt.Errorf("GCE networks in legacy mode are not supported.  Please convert to auto mode or specify a different network.")
		}
		empty := &Network{}
		if !reflect.DeepEqual(empty, changes) {
			return fmt.Errorf("cannot apply changes to Network: %v", changes)
		}
	}

	return nil
}

type terraformNetwork struct {
	Name                  *string `cty:"name"`
	IPv4Range             *string `cty:"ipv4_range"`
	Project               *string `cty:"project"`
	AutoCreateSubnetworks *bool   `cty:"auto_create_subnetworks"`
}

func (_ *Network) RenderTerraform(t *terraform.TerraformTarget, a, e, changes *Network) error {

View on GitHub (pinned to 4c8573c808)

Solutions

1. Migrate the GCE network from legacy to auto/custom subnet mode (gcloud compute networks update --switch-to-custom-subnet-mode) or use a different, non-legacy network
2. Point the cluster spec's NetworkID at a subnet-capable network

When it happens

Trigger: Thrown at upup/pkg/fi/cloudup/gcetasks/network.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/26b0e46108158ec2. Report an issue: GitHub.