$ cat main.tf.pub 
provider "proxmox" {
pm_user = ""
pm_password = ""
pm_api_url = "https://:8006/api2/json"
}

resource "proxmox_vm_qemu" "test" {
        name = "mirror.rd"
        desc = "Centos and EPEL Mirror"
        target_node = "pve01"
  #force_create = true
        clone = "terraform-centos-template"
        storage = "pve-data-lvm"
        cores = 2
        sockets = 1
        memory = 4096
        disk_gb = 1000
        nic = "virtio"
        bridge = "vmbr1"
        ssh_forward_ip = "x.x.x.x"
        ssh_user = "xxx"
        ssh_private_key = <<EOF
-----BEGIN RSA PRIVATE KEY-----
-----END RSA PRIVATE KEY-----
EOF

        os_type = "centos"
        os_network_config = <<EOF
auto eth0
iface eth0 inet dhcp
EOF

        provisioner "remote-exec" {
                inline = [
                        "/usr/sbin/ip a"
                ]
        }
  provisioner "proxmox" {
    action = "sshbackward"
  }

}

disk - (Optional)
  id (Required)
  type (Required)
  storage (Required)
  storage_type (Optional; defaults to dir) One of PVE     types as described in their documentation.
  size (Required)