aws_ecs_cluster: Deprecate capacity_providers and default_capacity_provider_strategy

[YakDriver]

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Terraform CLI and Terraform AWS Provider Version

Terraform v1.1.4
provider registry.terraform.io/hashicorp/aws v3.73.0

Affected Resource(s)

• aws_ecs_cluster

Terraform Configuration Files

Please include all Terraform configurations required to reproduce the bug. Bug reports without a functional reproduction may be closed without investigation.

resource "aws_ecs_cluster" "indestructable" { 
  name = "show_tf_cp_flaw"

  capacity_providers = [aws_ecs_capacity_provider.cp.name]

  default_capacity_provider_strategy {
    capacity_provider = aws_ecs_capacity_provider.cp.name
  }
}

resource "aws_ecs_capacity_provider" "cp" {
  name = "show_tf_cp_flaw"

  auto_scaling_group_provider {
    auto_scaling_group_arn = aws_autoscaling_group.asg.arn

    managed_scaling {
      status          = "ENABLED"
      target_capacity = 80
    }
  }
}

resource "aws_autoscaling_group" "asg" {
  min_size = 2
  ....
}

Debug Output

Error: Error deleting ECS cluster: ClusterContainsContainerInstancesException: The Cluster cannot be deleted while Container Instances are active or draining.

Expected Behavior

Clusters with capacity providers can be created and destroyed without error.

Actual Behavior

Error from cluster not being empty.

As described by @brikis98, the design of capacity providers is broken as it creates an invalid dependency chain: aws_ecs_cluster -> aws_ecs_capacity_provider -> aws_autoscaling_group (-> aws_ecs_cluster). This chain isn't valid, because on destroy, Terraform will try to delete aws_ecs_cluster first, but it can't, because the aws_autoscaling_group (has instances in the cluster and) hasn't been deleted.

Using the aws_ecs_cluster arguments capacity_providers and default_capacity_provider_strategy leads to this problem and is the flawed design. As a result, we need a new association resource (see #22672) and to deprecate these arguments (this issue).

References

• Terraform fails to destroy autoscaling group if scale in protection is enabled #5278
• Add support for ECS capacity providers #11150
• Add support for ECS capacity providers #11151
• Updating ECS service capacity provider strategy replaces resource #11351
• aws_ecs_cluster with capacity_providers cannot be destroyed #11409
• aws_ecs_capacity_provider_attachment #11531
• New Resource: aws_ecs_cluster_capacity_providers #22672

[github-actions]

This functionality has been released in v4.0.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

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