(aws-elasticloadbalancingv2): Add the weighted_random load balancing algorithm

[gillesbergerp]

Describe the feature

In 2023, Automatic Target Weights (ATW), which includes anomaly detection and a load balancing algorithm called Weighted Random (per this announcement). This feature request is about adding support for specifying the weighted_random algorithm as well as enable anomaly mitigation.

The CFN documentation can be found here.

Use Case

Enable CDK users to make use of the new routing strategy.

Proposed Solution

No response

Other Information

References:

• https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-target-groups.html#automatic-target-weights
• https://aws.amazon.com/blogs/networking-and-content-delivery/improving-availability-with-application-load-balancer-automatic-target-weights/
• https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-elasticloadbalancingv2-targetgroup-targetgroupattribute.html

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

2.139.0

Environment details (OS name and version, etc.)

Linux

[khushail]

Hi @gillesbergerp ,thanks for requesting this and submitting a PR.
I see the CDK doc mentioning the support for the same algorithm -

load_balancing.algorithm.type - The load balancing algorithm determines how the load balancer selects targets when routing requests. The value is round_robin , least_outstanding_requests , or weighted_random . The default is round_robin .

[gillesbergerp]

Yes, that is correct. Given that the two other supported algorithms are supported properly (i.e., can be specified in the props when creating a target group), I believe that adding the remaining one is beneficial