hypercore_nic import generates empty vm_uuid and causes perpetual drift

[ighrairi]

Provider: scalecomputing/hypercore
Terraform version: 1.15.9
Provider version: 1.4.0

Summary:

When importing existing NICs using the hypercore_nic resource:

1. terraform plan -generate-config-out generates an empty vm_uuid.

2. Subsequent plans always show a change for vm_uuid, even immediately after a successful apply.

This causes perpetual drift and prevents imported NIC resources from reaching a stable state.

Reproduction:

Example VM

WinSRV2025_Template
UUID: cf43258f-65a3-1ed8-9d37-agf422987a24

The VM has a single VirtIO NIC with VLAN-ALL (blank VLAN).

Import Block

import {
  to = hypercore_nic.WinSRV2025_Template_nic1
  id = "${hypercore_vm.WinSRV2025_Template.id}:VIRTIO:0"

  #or  id = format("%s:%s:%d", hypercore_vm.WinSRV2025_Template.id, "VIRTIO", 0)
}

Generate Configuration

terraform plan -generate-config-out=nic.tf

Terraform will perform the following actions:

....
  # hypercore_nic.WinSRV2025_Template_nic1 will be imported

    resource "hypercore_nic" "WinSRV2025_Template_nic1" {
        id          = "cf43258f-65a3-1ed8-9d37-agf422987a24"
        mac_address = "7C:4C:58:93:1F:CE"
        type        = "VIRTIO"
        vlan        = 0
        vm_uuid     = null
    }

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

Generated resource

resource "hypercore_nic" "WinSRV2025_Template_nic1" {
  mac_address = "7C:4C:58:93:1F:CE"
  type        = "VIRTIO"
  vlan        = 0
  vm_uuid     = ""
}

Expected Behavior

The generated configuration should contain the parent VM UUID:

resource "hypercore_nic" "WinSRV2025_Template_nic1" {
  mac_address = "7C:4C:58:93:1F:CE"
  type        = "VIRTIO"
  vlan        = 0
  vm_uuid     = hypercore_vm.WinSRV2025_Template.id
}

After manually replacing the value vm_uuid = "" with:

vm_uuid = hypercore_vm.WinSRV2025_Template.id

and running:

terraform apply --auto-approve

the next terraform plan still reports:

# hypercore_nic.WinSRV2025_Template_nic1 will be updated in-place

+ vm_uuid = "cf43258f-65a3-1ed8-9d37-agf422987a24"

The behavior was not observed on a single VM only. I reproduced the same results with multiple imported hypercore_nic resources attached to different VMs:

terraform plan -generate-config-out generates an empty vm_uuid.
terraform apply completes successfully.
The next terraform plan still reports a change for vm_uuid.

The behavior is consistent across all imported NICs tested and as a workaround, and I am currently using the following lifecycle block in the hypercore_nic resource: :

lifecycle {
        ignore_changes = [
        vm_uuid
        ]
}

[ighrairi]

Update

After additional testing, I discovered that the issue may be related to the VM power state.

For NICs attached to powered-on VMs:

• terraform plan -generate-config-out correctly populates vm_uuid
• terraform apply succeeds
• subsequent terraform plan reports no changes

For NICs attached to powered-off VMs (templates in my case):

• terraform plan -generate-config-out returns vm_uuid = null
• generated configuration contains vm_uuid = ""
• subsequent plans show persistent drift on vm_uuid