Amazon Elastic Load Balancing Construct Library

AWS CDK v1 has reached End-of-Support on 2023-06-01. This package is no longer being updated, and users should migrate to AWS CDK v2.

For more information on how to migrate, see the Migrating to AWS CDK v2 guide.

The @aws-cdk/aws-elasticloadbalancing package provides constructs for configuring classic load balancers.

Configuring a Load Balancer

Load balancers send traffic to one or more AutoScalingGroups. Create a load balancer, set up listeners and a health check, and supply the fleet(s) you want to load balance to in the targets property.

declare const vpc: ec2.IVpc;
const lb = new elb.LoadBalancer(this, 'LB', {
  vpc,
  internetFacing: true,
  healthCheck: {
    port: 80,
  },
});

declare const myAutoScalingGroup: autoscaling.AutoScalingGroup;
lb.addTarget(myAutoScalingGroup);
lb.addListener({
  externalPort: 80,
});

The load balancer allows all connections by default. If you want to change that, pass the allowConnectionsFrom property while setting up the listener:

declare const mySecurityGroup: ec2.SecurityGroup;
declare const lb: elb.LoadBalancer;
lb.addListener({
  externalPort: 80,
  allowConnectionsFrom: [mySecurityGroup],
});