Attach an existing volume to ohpc master

This MR will allow data volume that is already present in an openstack project to be attached to master in OHPC framework. We can easily attach and detach these data volumes to the new xdmod instances without having to re-ingest the data.

ohpc-instance/main.tf

@@ -26,7 +26,7 @@ variable "floating_ip_ohpc" {type = string}
 
 variable "ohpc_user" {}
 variable "ssh_private_key" {}
-
+variable "vol_id" {}
 
 # creates details for the OHPC instance
 resource "openstack_compute_instance_v2" "ohpc" {
@@ -61,6 +61,12 @@ resource "openstack_compute_floatingip_associate_v2" "ohpc" {
   instance_id = openstack_compute_instance_v2.ohpc.id
 }
 
+# Attach a volume
+resource "openstack_compute_volume_attach_v2" "volume_attach" {
+  instance_id = openstack_compute_instance_v2.ohpc.id
+  volume_id   = var.vol_id
+}
+
 output "id" {
     value = openstack_compute_instance_v2.ohpc.id
 }