kubernetes/kops · error

malformed format of loadbalancer ID

Error message

malformed format of loadbalancer ID: %s, %d

What it means

ParseLoadBalancerID parses an Azure load balancer resource ID of the form /subscriptions/<sub>/resourceGroups/<rg>/providers/Microsoft.Network/loadBalancers/<lb>/... where the path must split into exactly 11 slash-separated segments. If the count differs, the ID is malformed and this error reports the observed segment count. Called by the load balancer task's Find and unit tests.

Solutions

1. Provide the full load balancer resource ID as expected by kOps (11 slash-delimited segments including the name segment).
2. Fetch the canonical ID with `az network lb show -g <rg> -n <lb> --query id` and use it.
3. Count segments (strings.Split on "/") equals 11 before passing.
4. Verify the correct ID type is placed in the load balancer field of the spec, not a subnet/NSG ID.
5. Re-run kops update cluster after correcting the spec.

Example fix

// before
lbID = "/subscriptions/sub/resourceGroups/rg/providers/Microsoft.Network/loadBalancers"
// after
lbID = "/subscriptions/sub/resourceGroups/rg/providers/Microsoft.Network/loadBalancers/my-lb/frontendIPConfigurations/pip"

// Go: validate load balancer ID shape before parsing
func looksLikeAzureLBID(s string) bool {
    l := strings.Split(s, "/")
    return len(l) == 11 &&
        l[1] == "subscriptions" &&
        l[3] == "resourcegroups" &&
        strings.Contains(s, "loadBalancers/")
}
if !looksLikeAzureLBID(lbID) {
    return fmt.Errorf("expected full load balancer resource ID, got %q", lbID)
}

func isLoadBalancerID(s string) bool {
    return strings.HasPrefix(s, "/subscriptions/") &&
        strings.Contains(s, "loadBalancers/") &&
        strings.Count(s, "/") == 10
}

parsed, err := azure.ParseLoadBalancerID(lbID)
if err != nil {
    log.Printf("load balancer ID %q malformed (%v); check segment count is 11", lbID, err)
    return err
}

When it happens

Trigger: Calling ParseLoadBalancerID with a truncated load balancer path, a bare name, or an ID of another resource type — e.g. a 9-segment NSG-style ID or an 11-segment subnet ID with wrong resource hierarchy.

Common situations: Copy-pasting a truncated ID from CLI/portal output; passing a subnet or NSG ID into a load balancer field; load balancer name containing "/" (changes count); manual edits to cluster spec api loadBalancer configuration.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• failed to parse subnet ID
• malformed format of NetworkSecurityGroup ID
• malformed format of PublicIPAddress ID
• malformed format of subnet ID
• error parsing etcd cluster tag

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/8a84aa103b780364. Report an issue: GitHub.

Appendix: source

Thrown at upup/pkg/fi/cloudup/azure/azure_utils.go:138

	SubscriptionID    string
	ResourceGroupName string
	LoadBalancerName  string
}

// String returns the load balancer ID in the path format.
func (lb *LoadBalancerID) String() string {
	return fmt.Sprintf("/subscriptions/%s/resourceGroups/%s/providers/Microsoft.Network/loadbalancers/%s/backendAddressPools/LoadBalancerBackEnd",
		lb.SubscriptionID,
		lb.ResourceGroupName,
		lb.LoadBalancerName,
	)
}

// ParseLoadBalancerID parses a given load balancer ID string and returns a LoadBalancerID.
func ParseLoadBalancerID(lb string) (*LoadBalancerID, error) {
	l := strings.Split(lb, "/")
	if len(l) != 11 {
		return nil, fmt.Errorf("malformed format of loadbalancer ID: %s, %d", lb, len(l))
	}
	return &LoadBalancerID{
		SubscriptionID:    l[2],
		ResourceGroupName: l[4],
		LoadBalancerName:  l[8],
	}, nil
}

// PublicIPAddressID contains the resource ID/names required to construct a PublicIPAddress ID.
type PublicIPAddressID struct {
	SubscriptionID      string
	ResourceGroupName   string
	PublicIPAddressName string
}

// String returns the PublicIPAddress ID in the path format.
func (s *PublicIPAddressID) String() string {
	return fmt.Sprintf("/subscriptions/%s/resourceGroups/%s/providers/Microsoft.Network/publicIPAddresss/%s",

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