kubernetes/kops · error

listing VMSSs: %w

Error message

listing VMSSs: %w

What it means

Wrapped when paging through virtual machine scale sets in a resource group fails in vmScaleSetsClientImpl.List (used by kops cloud verification's Run). As with vnet List, a ResourceGroupNotFound ResponseError is tolerated (returns nil, nil); every other pager error is wrapped. It signals that cluster inventory discovery could not enumerate VMSS instances.

Source

Thrown at upup/pkg/fi/cloudup/azure/vmscaleset.go:70

	}
	return &resp.VirtualMachineScaleSet, nil
}

func (c *vmScaleSetsClientImpl) List(ctx context.Context, resourceGroupName string) ([]*compute.VirtualMachineScaleSet, error) {
	if resourceGroupName == "" {
		return nil, nil
	}

	var l []*compute.VirtualMachineScaleSet
	pager := c.c.NewListPager(resourceGroupName, nil)
	for pager.More() {
		resp, err := pager.NextPage(ctx)
		if err != nil {
			var respErr *azcore.ResponseError
			if errors.As(err, &respErr) && respErr.ErrorCode == "ResourceGroupNotFound" {
				return nil, nil
			}
			return nil, fmt.Errorf("listing VMSSs: %w", err)
		}
		l = append(l, resp.Value...)
	}
	return l, nil
}

func (c *vmScaleSetsClientImpl) Get(ctx context.Context, resourceGroupName string, vmssName string) (*compute.VirtualMachineScaleSet, error) {
	opts := &compute.VirtualMachineScaleSetsClientGetOptions{
		Expand: to.Ptr(compute.ExpandTypesForGetVMScaleSetsUserData),
	}
	resp, err := c.c.Get(ctx, resourceGroupName, vmssName, opts)
	if err != nil {
		return nil, fmt.Errorf("getting VMSS: %w", err)
	}
	return &resp.VirtualMachineScaleSet, nil
}

func (c *vmScaleSetsClientImpl) Delete(ctx context.Context, resourceGroupName, vmssName string) error {

View on GitHub (pinned to 4c8573c808)

Solutions

1. Grant the principal Reader/Contributor on the resource group (check for AuthorizationFailed in the wrapped error)
2. Retry with backoff if the error is 429/throttling
3. Confirm the resource group name in the cluster spec matches Azure (missing groups return empty, other errors do not)
4. Inspect errors.Unwrap for the underlying azcore.ResponseError code

// Go: ensure RBAC read access before enumerating VMSSs
// az role assignment create --assignee <principal> --role Reader --resource-group <rg>
if resourceGroup == "" {
    return fmt.Errorf("resource group is required to list VMSSs")
}

func isThrottled(err error) bool {
    var respErr *azcore.ResponseError
    return errors.As(err, &respErr) && respErr.StatusCode == http.StatusTooManyRequests
}

vmssList, err := vmssClient.List(ctx, rg)
if err != nil {
    var respErr *azcore.ResponseError
    if errors.As(err, &respErr) && respErr.StatusCode == http.StatusTooManyRequests {
        time.Sleep(retryAfter(respErr))
        vmssList, err = vmssClient.List(ctx, rg)
    }
    if err != nil {
        return fmt.Errorf("VMSS enumeration failed (check RBAC/ResourceGroup): %w", err)
    }
}

When it happens

Trigger: List's pager.NextPage(ctx) returns an error other than ResponseError with ErrorCode ResourceGroupNotFound — e.g. AuthorizationFailed, TooManyRequests (429), or a transient network failure.

Common situations: Verification against a cluster whose resource group was deleted concurrently (non-404 error path); service principal lacking Microsoft.Compute read; ARM throttling during large verifications; SDK paging across many VMSSs hitting intermittent failures.

Related errors

• creating/updating VMSS: %w
• waiting for VMSS create/update: %w
• listing virtual networks: %w
• expected exactly one subnet for InstanceGroup %q; subnets wa
• unexpected subnet type: for InstanceGroup %q; type was %s

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/c6c904f9524e4d2a. Report an issue: GitHub.