Failed to change root disk format when deploying vm from template

Hi folks,

I am experimenting with latest vsphere 2.2.0 to deploy vm from an existing template. The template’s disk format is thin provisioned. however i would like to create a VM from it with its root disk format change to use “Thick Provision Lazy Zeroed”. Following is how i configured the disk for the vm. I was expecting it will customize the root disk (unit_number=0) as it described to use thick provisioning. But i got a vm up and running with 2 disks. The root disk is in thin provisioning, and the additional disk is “Thick Provision Lazy Zeroed”. I am little confused by this. I may misunderstand something, would you please shed some lights on it? I just need to create a vm with only root disk with “Thick Provision Lazy Zeroed”, how could I achieve that? Thanks in advance!

  disk {
    label             = "disk0"
    thin_provisioned  = false
    eagerly_scrub     = false
    size              = 64
    datastore_id      =
    unit_number       = 0