ALB weighted target groups

[houstonj1]

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Description

There are new features on ALBs that allow for multiple target groups on a listener with a weighted priority. The potential configuration would allow for multiple action blocks on a aws_lb_listener_rule with a priority included.

AWS Reference: https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-target-groups.html

New or Affected Resource(s)

• aws_lb_listener_rule

Potential Terraform Configuration

resource "aws_alb_listener_rule" "my_lb_listener_rule" {
  listener_arn = ...
  priority     = ...

  action {
    type             = "forward"
    target_group_arn = arn_1
    priority = 8                            # 80% to target 1
  }

  action {
    type             = "forward"
    target_group_arn = arn_2
    priority = 2                            # 20% to target 2
  }

  condition {
    ....
  }
}

References

• Support ALB weighted target groups #10942

[DrMerlin]

Using 8 for 80% and 2 for 20% seems odd to me. Is that from the AWS API? Or just something that seemed good to you, James?

[houstonj1]

Using 8 for 80% and 2 for 20% seems odd to me. Is that from the AWS API? Or just something that seemed good to you, James?

Great question @DrMerlin! AWS offers values 0-999 for target weights, so there is a wide range of granularity to use. My example above was for simplicity :)

[bflad]

Hi @houstonj1 👋 Thank you for submitting this. This appears to be a duplicate or very similar to #10942, so to consolidate any discussions and efforts, I'm going to close this issue in preference of the earlier one. Please upvote and follow that issue for further updates.

[houstonj1]

Thanks @bflad, I see there was a PR merged related to that, which was closed. The purpose of this was to make it visible again. Thank you!

[bflad]

#10942 is still open -- one of the referenced pull requests (#8268) was indeed merged with similar, but unrelated functionality.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!