EMR configurations field forcing new EMR cluster when path changes

[cpower]

Hi there,

Running terraform apply on a Terraform managed EMR cluster that uses a path.module reference to configurations.json with remote state, when the path to the file changes, causes Terraform to destroy the EMR cluster and create a new one because the path to the configurations.json file is stored in the Terraform state which forces a new resource.

Terraform Version

Terraform v0.8.5

Affected Resource(s)

• aws_emr_cluster

Terraform Configuration Files

resource "aws_emr_cluster" "emr" {
  name = "${var.cluster_name}"
  release_label = "${var.release_label}"
  applications  = ["${split(",",var.applications)}"]
  service_role  = "${var.service_role}"
  log_uri  = "s3n://${var.s3_bucket}"
  master_instance_type = "${var.master_instance_type}"
  core_instance_type   = "${var.core_instance_type}"
  core_instance_count  = "${var.core_instance_count}"
  ec2_attributes {
    key_name = "${var.ec2_key_name}"
    subnet_id = "${data.aws_subnet.subnet.id}"
    instance_profile = "${var.ec2_instance_profile}"
    service_access_security_group = "${var.security_groups["emr_service_access"]}"
    emr_managed_master_security_group = "${var.security_groups["emr_managed_master"]}"
    emr_managed_slave_security_group  = "${var.security_groups["emr_managed_slave"]}"
    additional_master_security_groups = "${var.security_groups["emr_additional_master"]}"
    additional_slave_security_groups  = "${var.security_groups["emr_additional_slave"]}"
  }
  configurations = "${path.module}/${var.configurations}"
}

Expected Behavior

Updating a Terraform managed EMR cluster that uses a path.module reference to a configurations JSON file from a different path/machine when using remote state should not create and destroy a new EMR cluster.

Actual Behavior

Running terraform apply on a Terraform managed EMR cluster that uses a path.module reference, causes Terraform to destroy the EMR cluster and create a new one because the path to the configurations.json file is stored in the Terraform state.

Steps to Reproduce

Please list the steps required to reproduce the issue, for example:

1. terraform apply to create an EMR cluster on MachineA that has a path.module reference to a configurations.json file (use remote state)
2. Move to MachineB or simply change the path to the Terraform code
3. Make no other changes and runterraform apply, Terraform should destroy the EMR cluster and create a new one

References

Related Issues
#8754
#7927

[errriclee]

According to

terraform/builtin/providers/aws/resource_aws_emr_cluster.go

Line 764 in a8e4a9b

if err := readBodyJson(input, &configsOut); err != nil {

you can specify the contents of the file as well, instead of the file path. Using a template_file as the value of configurations will work and not cause unnecessary diff's.

I have tested this with the latest 0.9.5. I did not check which version this first appeared.

[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 have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.