Add option to disable iallocator use in QA

By default some QA tests use iallocators. It is now possible to disable
iallocators in QA, so that QA doesn't force having iallocators set up.
The affected tests have now alternatives pathways.

Signed-off-by: Bernardo Dal Seno <bdalseno@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

qa/qa-sample.json

@@ -164,7 +164,8 @@
     "burnin-check-instances": false,
     "burnin-rename": "xen-test-rename",
     "burnin-reboot": true,
-    "reboot-types": ["soft", "hard", "full"]
+    "reboot-types": ["soft", "hard", "full"],
+    "use-iallocators": false
   },
 
   "# vim: set syntax=javascript :": null

qa/qa_instance.py

@@ -485,19 +485,23 @@ def TestReplaceDisks(instance, pnode, snode, othernode):
     cmd.append(instance["name"])
     return cmd
 
+  options = qa_config.get("options", {})
+  use_ialloc = options.get("use-iallocators", True)
   for data in [
     ["-p"],
     ["-s"],
-    ["--new-secondary=%s" % othernode["primary"]],
-    ["-I", constants.DEFAULT_IALLOCATOR_SHORTCUT],
+    # A placeholder; the actual command choice depends on use_ialloc
+    None,
+    # Restore the original secondary
+    ["--new-secondary=%s" % snode["primary"]],
     ]:
+    if data is None:
+      if use_ialloc:
+        data = ["-I", constants.DEFAULT_IALLOCATOR_SHORTCUT]
+      else:
+        data = ["--new-secondary=%s" % othernode["primary"]]
     AssertCommand(buildcmd(data))
 
-  # Restore the original secondary, if needed
-  currsec = _GetInstanceInfo(instance)["nodes"][1]
-  if currsec != snode["primary"]:
-    AssertCommand(buildcmd(["--new-secondary=%s" % snode["primary"]]))
-
   AssertCommand(buildcmd(["-a"]))
   AssertCommand(["gnt-instance", "stop", instance["name"]])
   AssertCommand(buildcmd(["-a"]), fail=True)
@@ -541,22 +545,31 @@ def TestRecreateDisks(instance, pnode, snode, othernodes):
   @param othernodes: list/tuple of nodes where to temporarily recreate disks
 
   """
+  options = qa_config.get("options", {})
+  use_ialloc = options.get("use-iallocators", True)
   other_seq = ":".join([n["primary"] for n in othernodes])
   orig_seq = pnode["primary"]
   if snode:
     orig_seq = orig_seq + ":" + snode["primary"]
   # These fail because the instance is running
   _AssertRecreateDisks(["-n", other_seq], instance, fail=True, destroy=False)
-  _AssertRecreateDisks(["-I", "hail"], instance, fail=True, destroy=False)
+  if use_ialloc:
+    _AssertRecreateDisks(["-I", "hail"], instance, fail=True, destroy=False)
+  else:
+    _AssertRecreateDisks(["-n", other_seq], instance, fail=True, destroy=False)
   AssertCommand(["gnt-instance", "stop", instance["name"]])
   # Disks exist: this should fail
   _AssertRecreateDisks([], instance, fail=True, destroy=False)
   # Recreate disks in place
   _AssertRecreateDisks([], instance)
   # Move disks away
-  _AssertRecreateDisks(["-I", "hail"], instance)
-  # Move disks somewhere else
-  _AssertRecreateDisks(["-I", constants.DEFAULT_IALLOCATOR_SHORTCUT], instance)
+  if use_ialloc:
+    _AssertRecreateDisks(["-I", "hail"], instance)
+    # Move disks somewhere else
+    _AssertRecreateDisks(["-I", constants.DEFAULT_IALLOCATOR_SHORTCUT],
+                         instance)
+  else:
+    _AssertRecreateDisks(["-n", other_seq], instance)
   # Move disks back
   _AssertRecreateDisks(["-n", orig_seq], instance, check=False)
   # This and InstanceCheck decoration check that the disks are working