code: func (c *Cloud) UpdateLoadBalancer(clusterName string, service *v1.Service, nodes []*v1.Node) error {
  	instances, err := c.getInstancesByNodeNamesCached(nodeNames(nodes))
  	if err != nil {
  		return err
  	}
  
  	loadBalancerName := cloudprovider.GetLoadBalancerName(service)
  	lb, err := c.describeLoadBalancer(loadBalancerName)
  	if err != nil {
  		return err
  	}
  
  	if lb == nil {
  		return fmt.Errorf("Load balancer not found")
  	}
  
  	err = c.ensureLoadBalancerInstances(orEmpty(lb.LoadBalancerName), lb.Instances, instances)
  	if err != nil {
  		return nil
  	}
  
  	err = c.updateInstanceSecurityGroupsForLoadBalancer(lb, instances)
  	if err != nil {
  		return err
  	}
  
  	return nil
  }
docs: // UpdateLoadBalancer implements LoadBalancer.UpdateLoadBalancer