AWS::ElasticLoadBalancingV2::ListenerRule-Action-ForwardConfig

[callado4]

1. Title

AWS::ElasticLoadBalancingV2::ListenerRule-Action-ForwardConfig

2. Scope of request

d) new option for an existing attribute is desired

Weighted Target Groups were just recently added to ALB but it's not yet in Cloudformation.

The documentation in Cloudformation does mention the usage of ForwardConfig in the TargetGroupARN section of Action but there is no ForwardConfig attribute available yet for ListenerRule-Action

The Amazon Resource Name (ARN) of the target group. Specify only when Type is forward and you want to route to a single target group. To route to one or more target groups, use ForwardConfig instead.
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-elasticloadbalancingv2-listener-defaultactions.html

The API Reference for the corresponding property ForwardActionConfig has been updated:
https://docs.aws.amazon.com/elasticloadbalancing/latest/APIReference/API_ForwardActionConfig.html

3. Expected behavior

In Create, the listenerRule should create a listener with support for forwardConfig configuration, including defining multiple target groups with varying weights.

in Update, it would be very nice if when adding a target group or increasing an existing rule from a weight of 0 to >0, to wait until the target group is healthy before applying the change. This would allow us to deploy a different version of a service in one cloudformation update, instead of first ensuring that we have a healthy target group before sending requests to it.

4. Suggest specific test cases

One of the reasons for us to use weighted target groups is to deploy new changes to a subset of users. We would like to have a listener that can send traffic to a "canary" target group based on a Cloudformation update, but we would also like to setup this "canary" target group and/or set of services/servers behind the target group with the same cloudformation update. In other words, like a I mentioned above when updating a ForwardConfig with either a new target group or increasing a target group's weight from 0 to >0, the target group should be healthy before it starts to receive traffic.

5. Helpful Links to speed up research and evaluation

Updated API docs at https://docs.aws.amazon.com/elasticloadbalancing/latest/APIReference/API_ForwardActionConfig.html

Weighted target groups aws blog post - it uses cdk to create the initial stack, but then specifies to use the console for making weight changes: https://aws.amazon.com/blogs/aws/new-application-load-balancer-simplifies-deployment-with-weighted-target-groups/

6. Category (required) - Will help with tagging and be easier to find by other users to +1

1. Compute

7. Any additional context (optional)

Would love to be able to make these changes natively using the AWS CDK too :)

[PatMyron]

AWS::ElasticLoadBalancingV2::ListenerRule.Action documentation

release history

related issue