AWS DMS Tasks fails with "Invalid task settings JSON"

[ghost]

This issue was originally opened by Alien2150 as hashicorp/terraform#21918. It was migrated here as a result of the provider split. The original body of the issue is below.

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Hello there,

I noticed something odd when using the terraform dms task module. So what I could see is that terraform apply for the first time will create the task. Rerunning it afterwards with the same settings will crash it.

Terraform Version

Terraform v0.11.13
+ provider.aws v1.60.0

Terraform Configuration Files

# Setup dms aurora -> redshift
resource "aws_dms_endpoint" "source" {
  endpoint_id   = "source-db-${terraform.workspace}"
  endpoint_type = "source"
  engine_name   = "postgres"
  port          = "${element(split(":", var.bi_export_db_source_host), 1)}"
  server_name   = "${element(split(":", var.bi_export_db_source_host), 0)}"
  database_name = "${var.bi_export_db_source_name}"
  password      = "${var.bi_export_db_source_password}"
  username      = "${var.bi_export_db_source_username}"
}

resource "aws_dms_endpoint" "target" {
  endpoint_id   = "target-db-${terraform.workspace}"
  endpoint_type = "target"
  engine_name   = "redshift"
  # Redshift creds
  port          = "${element(split(":", var.bi_export_db_target_host), 1)}"
  server_name   = "${element(split(":", var.bi_export_db_target_host), 0)}"
  database_name = "${var.bi_export_db_target_name}"
  password      = "${var.bi_export_db_target_password}"
  username      = "${var.bi_export_db_target_username}"
}


resource "aws_dms_replication_subnet_group" "replication_subnet_group" {
  replication_subnet_group_description = "Subnet Replication Group ${terraform.workspace}"
  replication_subnet_group_id          = "subnet-group-${terraform.workspace}"
  subnet_ids                           = ["${data.aws_subnet_ids.private-subnet-ids.ids}"]
  tags                                 = {
    Environment = "${terraform.workspace}"
  }
}

resource "aws_dms_replication_instance" "replication_instance" {
  allocated_storage           = 40
  auto_minor_version_upgrade  = true
  replication_instance_class  = "${lookup(var.node-type, terraform.workspace)}"
  replication_instance_id     = "bi-migration-${terraform.workspace}"
  engine_version              = "${lookup(var.engine-version, terraform.workspace)}"
  publicly_accessible         = false
  replication_subnet_group_id = "${aws_dms_replication_subnet_group.replication_subnet_group.id}"
  vpc_security_group_ids      = ["${aws_security_group.dms_bi_import.id}", "${aws_security_group.dms_bi_export.id}"]
}


resource "aws_dms_replication_task" "replication_task" {
  migration_type            = "full-load-and-cdc" ## Define type (full-load, cdc, full-load-and-cdc)
  replication_instance_arn  = "${aws_dms_replication_instance.replication_instance.replication_instance_arn}"
  replication_task_id       = "bi-migration-task-${terraform.workspace}"
  source_endpoint_arn       = "${aws_dms_endpoint.source.endpoint_arn}"
  table_mappings            = "${var.table_mapping}" # mapping ... (if needed)
  target_endpoint_arn       = "${aws_dms_endpoint.target.endpoint_arn}"
}

Debug Output

If needed i can provide it

Crash Output

https://gist.github.com/Alien2150/37ff7c67089f1872ce234c09bc456747

Expected Behavior

Tasks should not have be changed.

Actual Behavior

Tasks assumes the task-settings have changed. And wants to recreate and fails with the error message.

Steps to Reproduce

1. terraform init
2. terraform apply
3. terraform apply

[ewbankkit]

Similar?

• aws_dms_replication_task replication_task_settings always reports as needing modification #1513
• dms_replication_task modifications to replication_task_settings requires recreation #552

[Alien2150]

@ewbankkit Sounds familiar. Think it can be closed

[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!