fix: Ignore changes to load_balancers and target_group_arns

[bryantbiggs]

Description

• Ignore changes to load_balancers and target_group_arns
• Ref Autoscaling Group - Target groups are getting removed hashicorp/terraform-provider-aws#14540

Motivation and Context

• Resolves feat: Add support for ignoring both desired_capacity and target_group_arns #250

Breaking Changes

• No

How Has This Been Tested?

• I have updated at least one of the examples/* to demonstrate and validate my change(s)
• I have tested and validated these changes using one or more of the provided examples/* projects

• I have executed pre-commit run -a on my pull request

[antonbabenko]

I tried to comprehend all the messages that were posted on this and linked issues and I don't understand WHY do we want to ignore changes in these additional arguments? They seem to be very important and it should have been addressed in the Terraform AWS provider, if their behavior is not consistent.

Am I missing something? Could you please explain briefly why this change is needed to be fixed in the module and not in provider?

[dusansusic]

@antonbabenko because each plan wants to remove asg instances from target groups. Next run will join it. This obviously causing downtime.

  ~ resource "aws_autoscaling_group" "idc" {
        id                               = "xxx-production-core-asg-a"
        name                             = "xxx-production-core-asg-a"
      ~ target_group_arns                = [
          - "arn:aws:elasticloadbalancing:eu-central-1:xxxx:targetgroup/tf-20231112171053124800000007/588de2cd885d173f",
        ]

next run:

  ~ resource "aws_autoscaling_group" "idc" {
        id                               = "xxx-production-core-asg-a"
        name                             = "xxx-production-core-asg-a"
      ~ target_group_arns                = [
          + "arn:aws:elasticloadbalancing:eu-central-1:xxxx:targetgroup/tf-20231112171053124800000007/588de2cd885d173f",
        ]

[dusansusic]

also, @antonbabenko and @bryantbiggs from this doc we can find:

If aws_autoscaling_attachment resources reference your ASG configurations, you will need to add the lifecycle configuration block with an ignore_changes argument to prevent Terraform non-empty plans (i.e., forcing resource update) during the next state refresh.

[antonbabenko]

Thanks for the brief explanation, @dusansusic ! It is very clear to me now. Time to merge. 👌

[antonbabenko]

This PR is included in version 7.3.1 🎉

[bryantbiggs]

ya'll beat me to it 😅 - I was thinking about this a bit more last night and was going to add the TODOs, so I've added them in #253 along with a bit more explanation of how and why we got here

[kkumtree]

I appreciate that my (but failed) pull request motivated you to make your pull request.

[github-actions]

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