There are more AWS SDK examples available in the [AWS Doc SDK Examples](https://github.com/awsdocs/aws-doc-sdk-examples) GitHub repo.
# Use `CreateLoadBalancer` with an AWS SDK or CLI
`CreateLoadBalancer`
The following code examples show how to use `CreateLoadBalancer`.
Action examples are code excerpts from larger programs and must be run in context. You can see this action in context in the following code examples:
+ [Build and manage a resilient service](elastic-load-balancing-v2_example_cross_ResilientService_section.md)
+ [Getting started with Elastic Load Balancing](elastic-load-balancing-v2_example_elastic_load_balancing_v2_GettingStarted_058_section.md)
------
#### [ .NET ]
**SDK for .NET**
There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/dotnetv3/cross-service/ResilientService/ElasticLoadBalancerActions#code-examples).
```
///
/// Create an Elastic Load Balancing load balancer that uses the specified subnets
/// and forwards requests to the specified target group.
///
/// The name for the new load balancer.
/// Subnets for the load balancer.
/// Target group for forwarded requests.
/// The new LoadBalancer object.
public async Task CreateLoadBalancerAndListener(string name, List subnetIds, TargetGroup targetGroup)
{
var createLbResponse = await _amazonElasticLoadBalancingV2.CreateLoadBalancerAsync(
new CreateLoadBalancerRequest()
{
Name = name,
Subnets = subnetIds
});
var loadBalancerArn = createLbResponse.LoadBalancers[0].LoadBalancerArn;
// Wait for load balancer to be available.
var loadBalancerReady = false;
while (!loadBalancerReady)
{
try
{
var describeResponse =
await _amazonElasticLoadBalancingV2.DescribeLoadBalancersAsync(
new DescribeLoadBalancersRequest()
{
Names = new List() { name }
});
var loadBalancerState = describeResponse.LoadBalancers[0].State.Code;
loadBalancerReady = loadBalancerState == LoadBalancerStateEnum.Active;
}
catch (LoadBalancerNotFoundException)
{
loadBalancerReady = false;
}
Thread.Sleep(10000);
}
// Create the listener.
await _amazonElasticLoadBalancingV2.CreateListenerAsync(
new CreateListenerRequest()
{
LoadBalancerArn = loadBalancerArn,
Protocol = targetGroup.Protocol,
Port = targetGroup.Port,
DefaultActions = new List()
{
new Action()
{
Type = ActionTypeEnum.Forward,
TargetGroupArn = targetGroup.TargetGroupArn
}
}
});
return createLbResponse.LoadBalancers[0];
}
```
+ For API details, see [CreateLoadBalancer](https://docs.aws.amazon.com/goto/DotNetSDKV3/elasticloadbalancingv2-2015-12-01/CreateLoadBalancer) in *AWS SDK for .NET API Reference*.
------
#### [ CLI ]
**AWS CLI**
**Example 1: To create an Internet-facing load balancer**
The following `create-load-balancer` example creates an Internet-facing Application Load Balancer and enables the Availability Zones for the specified subnets.
```
aws elbv2 create-load-balancer \
--name my-load-balancer \
--subnets subnet-b7d581c0 subnet-8360a9e7
```
Output:
```
{
"LoadBalancers": [
{
"Type": "application",
"Scheme": "internet-facing",
"IpAddressType": "ipv4",
"VpcId": "vpc-3ac0fb5f",
"AvailabilityZones": [
{
"ZoneName": "us-west-2a",
"SubnetId": "subnet-8360a9e7"
},
{
"ZoneName": "us-west-2b",
"SubnetId": "subnet-b7d581c0"
}
],
"CreatedTime": "2017-08-25T21:26:12.920Z",
"CanonicalHostedZoneId": "Z2P70J7EXAMPLE",
"DNSName": "my-load-balancer-424835706.us-west-2.elb.amazonaws.com",
"SecurityGroups": [
"sg-5943793c"
],
"LoadBalancerName": "my-load-balancer",
"State": {
"Code": "provisioning"
},
"LoadBalancerArn": "arn:aws:elasticloadbalancing:us-west-2:123456789012:loadbalancer/app/my-load-balancer/50dc6c495c0c9188"
}
]
}
```
For more information, see [Tutorial: Create an Application Load Balancer using the AWS CLI](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/tutorial-application-load-balancer-cli.html) in the *User Guide for Application Load Balancers*.
**Example 2: To create an internal load balancer**
The following `create-load-balancer` example creates an internal Application Load Balancer and enables the Availability Zones for the specified subnets.
```
aws elbv2 create-load-balancer \
--name my-internal-load-balancer \
--scheme internal \
--subnets subnet-b7d581c0 subnet-8360a9e7
```
Output:
```
{
"LoadBalancers": [
{
"Type": "application",
"Scheme": "internal",
"IpAddressType": "ipv4",
"VpcId": "vpc-3ac0fb5f",
"AvailabilityZones": [
{
"ZoneName": "us-west-2a",
"SubnetId": "subnet-8360a9e7"
},
{
"ZoneName": "us-west-2b",
"SubnetId": "subnet-b7d581c0"
}
],
"CreatedTime": "2016-03-25T21:29:48.850Z",
"CanonicalHostedZoneId": "Z2P70J7EXAMPLE",
"DNSName": "internal-my-internal-load-balancer-1529930873.us-west-2.elb.amazonaws.com",
"SecurityGroups": [
"sg-5943793c"
],
"LoadBalancerName": "my-internal-load-balancer",
"State": {
"Code": "provisioning"
},
"LoadBalancerArn": "arn:aws:elasticloadbalancing:us-west-2:123456789012:loadbalancer/app/my-internal-load-balancer/5b49b8d4303115c2"
}
]
}
```
For more information, see [Tutorial: Create an Application Load Balancer using the AWS CLI](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/tutorial-application-load-balancer-cli.html) in the *User Guide for Application Load Balancers*.
**Example 3: To create a Network Load Balancer**
The following `create-load-balancer` example creates an Internet-facing Network Load Balancer and enables the Availability Zone for the specified subnet. It uses a subnet mapping to associate the specified Elastic IP address with the network interface used by the load balancer nodes for the Availability Zone.
```
aws elbv2 create-load-balancer \
--name my-network-load-balancer \
--type network \
--subnet-mappings SubnetId=subnet-b7d581c0,AllocationId=eipalloc-64d5890a
```
Output:
```
{
"LoadBalancers": [
{
"Type": "network",
"Scheme": "internet-facing",
"IpAddressType": "ipv4",
"VpcId": "vpc-3ac0fb5f",
"AvailabilityZones": [
{
"LoadBalancerAddresses": [
{
"IpAddress": "35.161.207.171",
"AllocationId": "eipalloc-64d5890a"
}
],
"ZoneName": "us-west-2b",
"SubnetId": "subnet-5264e837"
}
],
"CreatedTime": "2017-10-15T22:41:25.657Z",
"CanonicalHostedZoneId": "Z2P70J7EXAMPLE",
"DNSName": "my-network-load-balancer-5d1b75f4f1cee11e.elb.us-west-2.amazonaws.com",
"LoadBalancerName": "my-network-load-balancer",
"State": {
"Code": "provisioning"
},
"LoadBalancerArn": "arn:aws:elasticloadbalancing:us-west-2:123456789012:loadbalancer/net/my-network-load-balancer/5d1b75f4f1cee11e"
}
]
}
```
For more information, see [Tutorial: Create a Network Load Balancer using the AWS CLI](https://docs.aws.amazon.com/elasticloadbalancing/latest/network/network-load-balancer-cli.html) in the *User Guide for Network Load Balancers*.
**Example 4: To create a Gateway Load Balancer**
The following `create-load-balancer` example creates a Gateway Load Balancer and enables the Availability Zones for the specified subnets.
```
aws elbv2 create-load-balancer \
--name my-gateway-load-balancer \
--type gateway \
--subnets subnet-dc83f691 subnet-a62583f9
```
Output:
```
{
"LoadBalancers": [
{
"Type": "gateway",
"VpcId": "vpc-838475fe",
"AvailabilityZones": [
{
"ZoneName": "us-east-1b",
"SubnetId": "subnet-a62583f9"
},
{
"ZoneName": "us-east-1a",
"SubnetId": "subnet-dc83f691"
}
],
"CreatedTime": "2021-07-14T19:33:43.324000+00:00",
"LoadBalancerName": "my-gateway-load-balancer",
"State": {
"Code": "provisioning"
},
"LoadBalancerArn": "arn:aws:elasticloadbalancing:us-east-1:850631746142:loadbalancer/gwy/my-gateway-load-balancer/dfbb5a7d32cdee79"
}
]
}
```
For more information, see [Getting started with Gateway Load Balancers using the AWS CLI](https://docs.aws.amazon.com/elasticloadbalancing/latest/gateway/getting-started-cli.html) in the *User Guide for Gateway Load Balancers*.
+ For API details, see [CreateLoadBalancer](https://awscli.amazonaws.com/v2/documentation/api/latest/reference/elbv2/create-load-balancer.html) in *AWS CLI Command Reference*.
------
#### [ Java ]
**SDK for Java 2.x**
There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/usecases/resilient_service#code-examples).
```
/*
* Creates an Elastic Load Balancing load balancer that uses the specified
* subnets
* and forwards requests to the specified target group.
*/
public String createLoadBalancer(List subnetIds, String targetGroupARN, String lbName, int port,
String protocol) {
try {
List subnetIdStrings = subnetIds.stream()
.map(Subnet::subnetId)
.collect(Collectors.toList());
CreateLoadBalancerRequest balancerRequest = CreateLoadBalancerRequest.builder()
.subnets(subnetIdStrings)
.name(lbName)
.scheme("internet-facing")
.build();
// Create and wait for the load balancer to become available.
CreateLoadBalancerResponse lsResponse = getLoadBalancerClient().createLoadBalancer(balancerRequest);
String lbARN = lsResponse.loadBalancers().get(0).loadBalancerArn();
ElasticLoadBalancingV2Waiter loadBalancerWaiter = getLoadBalancerClient().waiter();
DescribeLoadBalancersRequest request = DescribeLoadBalancersRequest.builder()
.loadBalancerArns(lbARN)
.build();
System.out.println("Waiting for Load Balancer " + lbName + " to become available.");
WaiterResponse waiterResponse = loadBalancerWaiter
.waitUntilLoadBalancerAvailable(request);
waiterResponse.matched().response().ifPresent(System.out::println);
System.out.println("Load Balancer " + lbName + " is available.");
// Get the DNS name (endpoint) of the load balancer.
String lbDNSName = lsResponse.loadBalancers().get(0).dnsName();
System.out.println("*** Load Balancer DNS Name: " + lbDNSName);
// Create a listener for the load balance.
Action action = Action.builder()
.targetGroupArn(targetGroupARN)
.type("forward")
.build();
CreateListenerRequest listenerRequest = CreateListenerRequest.builder()
.loadBalancerArn(lsResponse.loadBalancers().get(0).loadBalancerArn())
.defaultActions(action)
.port(port)
.protocol(protocol)
.build();
getLoadBalancerClient().createListener(listenerRequest);
System.out.println("Created listener to forward traffic from load balancer " + lbName + " to target group "
+ targetGroupARN);
// Return the load balancer DNS name.
return lbDNSName;
} catch (ElasticLoadBalancingV2Exception e) {
e.printStackTrace();
}
return "";
}
```
+ For API details, see [CreateLoadBalancer](https://docs.aws.amazon.com/goto/SdkForJavaV2/elasticloadbalancingv2-2015-12-01/CreateLoadBalancer) in *AWS SDK for Java 2.x API Reference*.
------
#### [ JavaScript ]
**SDK for JavaScript (v3)**
There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cross-services/wkflw-resilient-service#code-examples).
```
const client = new ElasticLoadBalancingV2Client({});
const { LoadBalancers } = await client.send(
new CreateLoadBalancerCommand({
Name: NAMES.loadBalancerName,
Subnets: state.subnets,
}),
);
state.loadBalancerDns = LoadBalancers[0].DNSName;
state.loadBalancerArn = LoadBalancers[0].LoadBalancerArn;
await waitUntilLoadBalancerAvailable(
{ client },
{ Names: [NAMES.loadBalancerName] },
);
```
+ For API details, see [CreateLoadBalancer](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/elastic-load-balancing-v2/command/CreateLoadBalancerCommand) in *AWS SDK for JavaScript API Reference*.
------
#### [ PowerShell ]
**Tools for PowerShell V4**
**Example 1: This example creates new internet facing Application load balancer with two subnets.**
```
New-ELB2LoadBalancer -Type application -Scheme internet-facing -IpAddressType ipv4 -Name 'New-Test-ALB' -SecurityGroup 'sg-07c3414abb8811cbd' -subnet 'subnet-c37a67a6','subnet-fc02eea0'
```
**Output:**
```
AvailabilityZones : {us-east-1b, us-east-1a}
CanonicalHostedZoneId : Z35SXDOTRQ7X7K
CreatedTime : 12/28/19 2:58:03 PM
DNSName : New-Test-ALB-1391502222.us-east-1.elb.amazonaws.com
IpAddressType : ipv4
LoadBalancerArn : arn:aws:elasticloadbalancing:us-east-1:123456789012:loadbalancer/app/New-Test-ALB/dab2e4d90eb51493
LoadBalancerName : New-Test-ALB
Scheme : internet-facing
SecurityGroups : {sg-07c3414abb8811cbd}
State : Amazon.ElasticLoadBalancingV2.Model.LoadBalancerState
Type : application
VpcId : vpc-2cfd7000
```
+ For API details, see [CreateLoadBalancer](https://docs.aws.amazon.com/powershell/v4/reference) in *AWS Tools for PowerShell Cmdlet Reference (V4)*.
**Tools for PowerShell V5**
**Example 1: This example creates new internet facing Application load balancer with two subnets.**
```
New-ELB2LoadBalancer -Type application -Scheme internet-facing -IpAddressType ipv4 -Name 'New-Test-ALB' -SecurityGroup 'sg-07c3414abb8811cbd' -subnet 'subnet-c37a67a6','subnet-fc02eea0'
```
**Output:**
```
AvailabilityZones : {us-east-1b, us-east-1a}
CanonicalHostedZoneId : Z35SXDOTRQ7X7K
CreatedTime : 12/28/19 2:58:03 PM
DNSName : New-Test-ALB-1391502222.us-east-1.elb.amazonaws.com
IpAddressType : ipv4
LoadBalancerArn : arn:aws:elasticloadbalancing:us-east-1:123456789012:loadbalancer/app/New-Test-ALB/dab2e4d90eb51493
LoadBalancerName : New-Test-ALB
Scheme : internet-facing
SecurityGroups : {sg-07c3414abb8811cbd}
State : Amazon.ElasticLoadBalancingV2.Model.LoadBalancerState
Type : application
VpcId : vpc-2cfd7000
```
+ For API details, see [CreateLoadBalancer](https://docs.aws.amazon.com/powershell/v5/reference) in *AWS Tools for PowerShell Cmdlet Reference (V5)*.
------
#### [ Python ]
**SDK for Python (Boto3)**
There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/python/example_code/elastic-load-balancing#code-examples).
```
class ElasticLoadBalancerWrapper:
"""Encapsulates Elastic Load Balancing (ELB) actions."""
def __init__(self, elb_client: boto3.client):
"""
Initializes the LoadBalancer class with the necessary parameters.
"""
self.elb_client = elb_client
def create_load_balancer(
self,
load_balancer_name: str,
subnet_ids: List[str],
) -> Dict[str, Any]:
"""
Creates an Elastic Load Balancing load balancer that uses the specified subnets
and forwards requests to the specified target group.
:param load_balancer_name: The name of the load balancer to create.
:param subnet_ids: A list of subnets to associate with the load balancer.
:return: Data about the newly created load balancer.
"""
try:
response = self.elb_client.create_load_balancer(
Name=load_balancer_name, Subnets=subnet_ids
)
load_balancer = response["LoadBalancers"][0]
log.info(f"Created load balancer '{load_balancer_name}'.")
waiter = self.elb_client.get_waiter("load_balancer_available")
log.info(
f"Waiting for load balancer '{load_balancer_name}' to be available..."
)
waiter.wait(Names=[load_balancer_name])
log.info(f"Load balancer '{load_balancer_name}' is now available!")
except ClientError as err:
error_code = err.response["Error"]["Code"]
log.error(
f"Failed to create load balancer '{load_balancer_name}'. Error code: {error_code}, Message: {err.response['Error']['Message']}"
)
if error_code == "DuplicateLoadBalancerNameException":
log.error(
f"A load balancer with the name '{load_balancer_name}' already exists. "
"Load balancer names must be unique within the AWS region. "
"Please choose a different name and try again."
)
if error_code == "TooManyLoadBalancersException":
log.error(
"The maximum number of load balancers has been reached in this account and region. "
"You can delete unused load balancers or request an increase in the service quota from AWS Support."
)
log.error(f"Full error:\n\t{err}")
else:
return load_balancer
```
+ For API details, see [CreateLoadBalancer](https://docs.aws.amazon.com/goto/boto3/elasticloadbalancingv2-2015-12-01/CreateLoadBalancer) in *AWS SDK for Python (Boto3) API Reference*.
------