[Bug]: changes to initial_lifecycle_hook block of ASG does not force replacement

[dhrkumar]

Terraform Core Version

1.3.6

AWS Provider Version

5.23.1

Affected Resource(s)

• aws_autoscaling_group

Expected Behavior

When attempting to update initial_lifecycle_hook attribute like heartbeat_timeout in an auto scaling group, I would expect that aws_autoscaling_group to be replaced, as to apply expected hook configuration.

Actual Behavior

Terraform plan produces an inline update for aws_autoscaling_group with creating a new hook and deleting old hook, which actually does nothing as the hook block is only intended for create phase of ASG.

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # aws_autoscaling_group.asg will be updated in-place
  ~ resource "aws_autoscaling_group" "asg" {
        id                               = "terraform-20231031112905745500000001"
        name                             = "terraform-20231031112905745500000001"
        # (27 unchanged attributes hidden)

      - initial_lifecycle_hook {
          - default_result       = "CONTINUE" -> null
          - heartbeat_timeout    = 30 -> null
          - lifecycle_transition = "autoscaling:EC2_INSTANCE_LAUNCHING" -> null
          - name                 = "lifecycle-hook-update-test" -> null
        }
      + initial_lifecycle_hook {
          + default_result       = "CONTINUE"
          + heartbeat_timeout    = 40
          + lifecycle_transition = "autoscaling:EC2_INSTANCE_LAUNCHING"
          + name                 = "lifecycle-hook-update-test"
        }

        # (1 unchanged block hidden)
    }

Plan: 0 to add, 1 to change, 0 to destroy.

Relevant Error/Panic Output Snippet

No response

Terraform Configuration Files

resource "aws_iam_role" "role" {
  assume_role_policy = jsonencode({
    Version   = "2012-10-17"
    Statement = [
      {
        Action    = "sts:AssumeRole"
        Effect    = "Allow"
        Principal = {
          Service = "ec2.amazonaws.com"
        }
      },
    ]
  })
  name = "launch-template-ec2-role"
  path = "/ec2/instance/"
}
resource "aws_iam_instance_profile" "instance_profile" {
  name = "ec2-instance-profile"
  path = "/ec2/instance/"
  role = aws_iam_role.role.name
}

resource "aws_launch_template" "lt" {
  description   = "Launch template for ec2"
  image_id      = "ami-06ca3ca175f37dd66"
  instance_type = "t3.nano"
  name          = "ec2-linux-1"
  iam_instance_profile {
    arn = aws_iam_instance_profile.instance_profile.arn
  }
}

resource "aws_autoscaling_group" "asg" {
  availability_zones = ["us-east-1a"]
  launch_template {
    name    = aws_launch_template.lt.name
    version = "$Latest"
  }
  max_size         = 1
  min_size         = 1
  desired_capacity = 1
  initial_lifecycle_hook {
    lifecycle_transition = "autoscaling:EC2_INSTANCE_LAUNCHING"
    default_result       = "CONTINUE"
    name                 = "lifecycle-hook-update-test"
    heartbeat_timeout    = 30
  }
}

Steps to Reproduce

1. terraform apply
2. Change heartbeat_timeout value to 40
3. terraform apply
4. Verify the updated value in AWS using web console or CLI

Debug Output

No response

Panic Output

No response

Important Factoids

No response

References

#4714

Would you like to implement a fix?

Yes

[github-actions]

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[github-actions]

This functionality has been released in v5.25.0 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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