NLB: NetworkTargetGroup does not depend on NetworkListener

[inoutch]

I tried to deploy NLB with ECS Fargate, but I couldn't deploy Service of ECS because the following reason.

The target group with targetGroupArn arn:aws:elasticloadbalancing:ap-northeast-1:*****:targetgroup/*****/***** does not have an associated load balancer. (Service: AmazonECS; Status Code: 400; Error Code: InvalidParameterException; Request ID: *****)

I found that NetworkTargetGroup does not to depend on NetworkListener.
In addition, I found not to call targetGroup.registerListener(this) in only NLB.

https://github.com/awslabs/aws-cdk/blob/6f2569fd51e7b6152830d40b146ff5f2d607e4c2/packages/%40aws-cdk/aws-elasticloadbalancingv2/lib/nlb/network-listener.ts#L69
https://github.com/awslabs/aws-cdk/blob/6f2569fd51e7b6152830d40b146ff5f2d607e4c2/packages/%40aws-cdk/aws-elasticloadbalancingv2/lib/nlb/network-listener.ts#L60
https://github.com/awslabs/aws-cdk/blob/6f2569fd51e7b6152830d40b146ff5f2d607e4c2/packages/%40aws-cdk/aws-elasticloadbalancingv2/lib/shared/base-listener.ts#L38-L43

I think it should call this registerListener function as the same way as ALB.

https://github.com/awslabs/aws-cdk/blob/6f2569fd51e7b6152830d40b146ff5f2d607e4c2/packages/%40aws-cdk/aws-elasticloadbalancingv2/lib/alb/application-listener.ts#L252-L255

Is this bug?, or is there any reasons in only NLB?

[rix0rrr]

That's a bug. Thanks

[rix0rrr]

Ooh, I totally misunderstood what the error report was about.

Could you show some of your code please?

[rix0rrr]

Here's what the load balancer part should look like:

https://github.com/awslabs/aws-cdk/blob/master/packages/%40aws-cdk/aws-ecs/test/ec2/integ.lb-awsvpc-nw.ts#L36

[inoutch]

My source code where the error occurred is general constitution using NetworkLoadBalancer. I think the same error occurs replacing ALB with NLB in the test(integ.lb-awsvpc-nw) you pasted.

I think there is a cause in addTargetGroups(called by addTargets) method of NetworkListener class. In the addTargetGroups, _addDefaultTargetGroup is called, but I think that targetGroup.registerListener method should also be called together. By calling the registerListener method, NetworkTargetGroup depends on NetworkListener. This implementation is only in ALB, not in NLB. Therefore ALB succeed.

It is another small problem, but also I report that unhealthyThresholdCount of TargetGroup properties is not reflected.

Sorry for my bad english.