# AlternateTarget

Configuration for alternate target groups used in blue/green deployments with load balancers.

Extends: AlternateTarget
Implements: IAlternateTarget

- Source: [`aws-ecs/lib/alternate-target-configuration.ts`](https://github.com/aws/aws-cdk/blob/v2.276.0/packages/aws-cdk-lib/aws-ecs/lib/alternate-target-configuration.ts#L126)
- Type last changed: v2.211.0 · 13 Aug 2025

## Example

```ts
declare const cluster: ecs.Cluster;
declare const taskDefinition: ecs.TaskDefinition;
declare const blueTargetGroup: elbv2.ApplicationTargetGroup;
declare const greenTargetGroup: elbv2.ApplicationTargetGroup;
declare const prodListenerRule: elbv2.ApplicationListenerRule;

const service = new ecs.FargateService(this, 'Service', {
  cluster,
  taskDefinition,
  deploymentStrategy: ecs.DeploymentStrategy.LINEAR,
  linearConfiguration: {
    stepPercent: 10.0,
    stepBakeTime: Duration.minutes(5),
  },
});

const target = service.loadBalancerTarget({
  containerName: 'web',
  containerPort: 80,
  alternateTarget: new ecs.AlternateTarget('AlternateTarget', {
    alternateTargetGroup: greenTargetGroup,
    productionListener: ecs.ListenerRuleConfiguration.applicationListenerRule(prodListenerRule),
  }),
});

target.attachToApplicationTargetGroup(blueTargetGroup);
```

## Initializer

```ts
new AlternateTarget(id: string, props: AlternateTargetProps)
```

## Methods

- `bind(scope: IConstruct): AlternateTargetConfig` — Bind this configuration to a service.