ignore_changes used w/ aws_ecs_service causes "diffs didn't match"

[anosulchik]

Please refer #4950 I cannot reopen it so I've created new issue.

---

Looks like it still doesn't works as expected. Here's how to reproduce:

1. create ecs service with ignore_changes enabled for desired_count:

resource "aws_ecs_service" "issues_ecs_service" {
  name = "issues_${var.environment_name}"
  cluster = "${aws_ecs_cluster.cluster1.id}"
  task_definition = "${aws_ecs_task_definition.issues_task_def.arn}"
  desired_count = 2
  iam_role = "${var.ecs_service_role_arn}"

  load_balancer {
    elb_name = "${aws_elb.issues_service_elb.id}"
    container_name = "issues"
    container_port = 8443
  }

  lifecycle {
    ignore_changes = [ "desired_count" ]
  }
}

1. Change ecs desired count via ECS console or API call (we're doing it via AWS lambda).
2. Try to apply changes into ecs service e.g. set new task definition for it.

Here's the log:

2016/02/02 16:34:57 [DEBUG] root: eval: *terraform.EvalIf
2016/02/02 16:34:57 [DEBUG] root: eval: *terraform.EvalInterpolate
2016/02/02 16:34:57 [DEBUG] root: eval: *terraform.EvalGetProvider
2016/02/02 16:34:57 [DEBUG] root: eval: *terraform.EvalReadState
2016/02/02 16:34:57 [DEBUG] root: eval: *terraform.EvalDiff
2016/02/02 16:34:57 [DEBUG] root: eval: *terraform.EvalReadDiff
2016/02/02 16:34:57 [DEBUG] root: eval: *terraform.EvalCompareDiff
2016/02/02 16:34:57 [ERROR] aws_ecs_service.issues_ecs_service: diffs didn't match
2016/02/02 16:34:57 [ERROR] aws_ecs_service.issues_ecs_service: reason: extra attributes: desired_count
2016/02/02 16:34:57 [ERROR] aws_ecs_service.issues_ecs_service: diff one: *terraform.InstanceDiff{Attributes:map[string]*terraform.ResourceAttrDiff{"task_definition":*terraform.ResourceAttrDiff{Old:"arn:aws:ecs:us-east-1:xxx:task-definition/issues_service_Staging:25", New:"arn:aws:ecs:us-east-1:xxx:task-definition/issues_service_Staging:26", NewComputed:false, NewRemoved:false, NewExtra:interface {}(nil), RequiresNew:false, Type:0x0}}, Destroy:false, DestroyTainted:false}
2016/02/02 16:34:57 [ERROR] aws_ecs_service.issues_ecs_service: diff two: *terraform.InstanceDiff{Attributes:map[string]*terraform.ResourceAttrDiff{"task_definition":*terraform.ResourceAttrDiff{Old:"arn:aws:ecs:us-east-1:xxx:task-definition/issues_service_Staging:25", New:"arn:aws:ecs:us-east-1:xxx:task-definition/issues_service_Staging:26", NewComputed:false, NewRemoved:false, NewExtra:interface {}(nil), RequiresNew:false, Type:0x0}, "desired_count":*terraform.ResourceAttrDiff{Old:"4", New:"2", NewComputed:false, NewRemoved:false, NewExtra:interface {}(nil), RequiresNew:false, Type:0x0}}, Destroy:false, DestroyTainted:false}
2016/02/02 16:34:57 [ERROR] root: eval: *terraform.EvalCompareDiff, err: aws_ecs_service.issues_ecs_service: diffs didn't match during apply. This is a bug with Terraform and should be reported.
2016/02/02 16:34:57 [ERROR] root: eval: *terraform.EvalSequence, err: aws_ecs_service.issues_ecs_service: diffs didn't match during apply. This is a bug with Terraform and should be reported.
2016/02/02 16:34:57 [ERROR] root: eval: *terraform.EvalOpFilter, err: aws_ecs_service.issues_ecs_service: diffs didn't match during apply. This is a bug with Terraform and should be reported.
2016/02/02 16:34:57 [ERROR] root: eval: *terraform.EvalSequence, err: aws_ecs_service.issues_ecs_service: diffs didn't match during apply. This is a bug with Terraform and should be reported.
2016/02/02 16:34:57 [INFO] Exiting eval tree: aws_ecs_service.issues_ecs_service
2016/02/02 16:34:57 [DEBUG] vertex provider.aws (close), got dep: aws_ecs_service.issues_ecs_service
2016/02/02 16:34:57 [DEBUG] vertex root, got dep: provider.aws (close)
2016/02/02 16:34:57 [DEBUG] vertex root, got dep: provisioner.chef
2016/02/02 16:34:57 [DEBUG] vertex root, got dep: var.iam_instance_profile
2016/02/02 16:34:57 [DEBUG] vertex root, got dep: provisioner.file
2016/02/02 16:34:57 [DEBUG] vertex root, got dep: var.availability_zones

'terraform apply' starts working again without issues as soon as I return desired count to initial value (2).

Please let me know if there any options to resolve it. Thank you!

[phinze]

Hi @anosulchik - thanks for this report, I'm diving into ignore_changes fixes today and consolidating the effort in #5627

[ghost]

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