ECS fargate service with ALB deployed using CDK

Question

This is my first time trying to use CDK to deploy a Fargate service stack with an ALB configured in a separate stack. I tried to follow this example https://github.com/aws-samples/aws-cdk-examples/blob/master/typescript/ecs/cross-stack-load-balancer/split-at-listener.ts

Note: By itself the task definition and the service is getting deployed perfectly, however when I try to add a listener/target group and register the service with the target group then it fails with this error.

```
Resource handler returned message: "Invalid request provided: UpdateService error: Health check grace period is only valid for services config
ured to use load balancers (Service: AmazonECS; Status Code: 400; Error Code: InvalidParameterException; Request ID: c49473d9-f5d1-47c2-b113-3
0551d484d3f; Proxy: null)" (RequestToken: e68aef9e-ed8f-8d28-d29c-fec52c7339e0, HandlerErrorCode: InvalidRequest)
```

Answer

Can you check whether the service you created is using load balancing or not?

You cannot update an ECS service whether or not to use load balancing.

If you want to change it (i.e. from non-load balancing to load balancing or vice-versa), you need to re-create the service.

https://docs.aws.amazon.com/AmazonECS/latest/userguide/service-load-balancing.html#load-balancing-considerations

>You cannot add, remove, or change the load balancer configuration of an existing service.

ECS fargate service with ALB deployed using CDK

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