htools: read the disk template in Luxi and Rapi

Both these backends already have the data, we just need to use it.
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

htools/Ganeti/HTools/IAlloc.hs

@@ -66,8 +66,9 @@ parseBaseInstance n a = do
   mem   <- extract "memory"
   vcpus <- extract "vcpus"
   tags  <- extract "tags"
+  dt    <- extract "disk_template"
   let running = "running"
-  return (n, Instance.create n mem disk vcpus running tags True 0 0 DTDrbd8)
+  return (n, Instance.create n mem disk vcpus running tags True 0 0 dt)
 
 -- | Parses an instance as found in the cluster instance list.
 parseInstance :: NameAssoc -- ^ The node name-to-index association list

htools/Ganeti/HTools/Rapi.hs

@@ -119,8 +119,9 @@ parseInstance ktn a = do
   running <- extract "status" a
   tags <- extract "tags" a
   auto_balance <- extract "auto_balance" beparams
+  dt <- extract "disk_template" a
   let inst = Instance.create name mem disk vcpus running tags
-             auto_balance pnode snode DTDrbd8
+             auto_balance pnode snode dt
   return (name, inst)
 
 -- | Construct a node from a JSON object.