remove ensureSubnets check and update unit test to add AZ info

pkg/providers/v1/aws.go

@@ -4155,19 +4155,15 @@ func (c *Cloud) EnsureLoadBalancer(ctx context.Context, clusterName string, apiS
 			return nil, err
 		}
 
-		// try to get the existing subnets of existing LBs from AZs
+		// try to get the ensured subnets of the LBs from AZs
 		var ensuredSubnetIDs []string
 		var subnetCidrs []string
 		for _, az := range v2LoadBalancer.AvailabilityZones {
 			ensuredSubnetIDs = append(ensuredSubnetIDs, *az.SubnetId)
 		}
-		// for newly created LBs, the ensured subnets are nil since the loadbalancer.AvailabilityZones are none
-		// we use discovered subnets in this case
 		if len(ensuredSubnetIDs) == 0 {
-			klog.Infof("did not find existing subnets on LB %s, use discovered subnets %d", loadBalancerName, discoveredSubnetIDs)
-			subnetCidrs, err = c.getSubnetCidrs(discoveredSubnetIDs)
+			return nil, fmt.Errorf("did not find ensured subnets on LB %s", loadBalancerName)
 		} else {
-			klog.Infof("use exising subnets on LB %s, subnet IDs: %d", loadBalancerName, ensuredSubnetIDs)
 			subnetCidrs, err = c.getSubnetCidrs(ensuredSubnetIDs)
 		}
 		if err != nil {

pkg/providers/v1/aws_test.go

@@ -2759,6 +2759,12 @@ func (m *MockedFakeELBV2) CreateLoadBalancer(request *elbv2.CreateLoadBalancerIn
 		LoadBalancerName: request.Name,
 		Type:             aws.String(elbv2.LoadBalancerTypeEnumNetwork),
 		VpcId:            aws.String("vpc-abc123def456abc78"),
+		AvailabilityZones: []*elbv2.AvailabilityZone{
+			{
+				ZoneName: aws.String("us-west-2a"),
+				SubnetId: aws.String("subnet-abc123de"),
+			},
+		},
 	}
 	m.LoadBalancers = append(m.LoadBalancers, newLB)