code: func (az *Cloud) IsNodeUnmanaged(nodeName string) (bool, error) {
  	unmanagedNodes, err := az.GetUnmanagedNodes()
  	if err != nil {
  		return false, err
  	}
  
  	return unmanagedNodes.Has(nodeName), nil
  }
docs: // IsNodeUnmanaged returns true if the node is not managed by Azure cloud provider.
  // Those nodes includes on-prem or VMs from other clouds. They will not be added to load balancer
  // backends. Azure routes and managed disks are also not supported for them.