KVM instances get random data disk ids during creation

[jordan j]

Hi everyone,

We are using Cloudstack 4.19.0.1 with Debian12 KVM host as hypervisor. When
we try to create an instance (Debian12) with Terraform (version of provider
module 0.4.0), the additional disks are not being created in the specific
order we set:

resource "cloudstack_disk" "this" {
  for_each = {
    data = {
      disk_offering = var.data_volume_disk_offering
      size = var.data_volume_size
      device_id = 1  # /dev/xvdb
    }

    secret-store = {
      disk_offering = var.secret_store_volume_disk_offering
      size = var.secret_store_volume_size
      device_id = 9  # /dev/xvdj
    }
  }
}

We use the same code for XCP hosts and the disks there are created in the
specific order - /dev/xvdb is with the size we set for the "data" disk,
/dev/xvdj is with the size we set for "secrets" disk. However, on KVM the
disks are not being created in the specific order - sometimes /dev/vdb is
the data drive and /dev/vdc is the secrets drive, sometimes it's the
opposite.

Anyone with similar experience? Is there a way to "force" this order?

Regards,
Jordan