libvirt: avoid setting the memnodes where when it's not a supported o…

…ption

The current version of Libvirt in the gate doesn't support a memnode element
in the numa tune configuration. When requesting guest topology the instance
is crashing. Not setting the numa tune memnodes option when libvirt version
is less than the required minimum.

Change-Id: I99d0bb64bd6d698f2d5ce978cb3778bbad8eec91
Closes-Bug: #1415333

nova/tests/unit/virt/libvirt/test_driver.py

@@ -1144,6 +1144,27 @@ def test_get_guest_memory_backing_config_mempages_none(self):
             self.assertIsNone(self._test_get_guest_memory_backing_config(
                               'not_empty', 'not_empty', 'not_empty'))
 
+    def test_get_guest_numa_tune_memnodes(self):
+        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
+        guest_cpu_numa_config = objects.InstanceNUMATopology(cells=[
+                                objects.InstanceNUMACell(
+                                id=1, cpuset=set([0, 1]),
+                                memory=1024, pagesize=2048)])
+        memnodes = [vconfig.LibvirtConfigGuestNUMATuneMemNode()]
+        with mock.patch.object(host.Host, 'has_min_version',
+                               return_value=True):
+            self.assertIsNotNone(drvr._get_guest_numa_tune_memnodes(
+                              guest_cpu_numa_config, memnodes))
+            self.assertEqual(guest_cpu_numa_config.cells[0].id,
+                             memnodes[0].cellid)
+
+    def test_get_guest_numa_tune_memnodes_none(self):
+        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
+        with mock.patch.object(host.Host, 'has_min_version',
+                               return_value=False):
+            self.assertIsNone(drvr._get_guest_numa_tune_memnodes(
+                              'something', 'something'))
+
     @mock.patch.object(objects.Flavor, 'get_by_id')
     def test_get_guest_config_numa_host_instance_fit_w_cpu_pinset(self,
                                                                   mock_flavor):

nova/virt/libvirt/driver.py

@@ -366,6 +366,8 @@ def repr_method(self):
 MIN_LIBVIRT_FSFREEZE_VERSION = (1, 2, 5)
 # libvirt mempage size report
 MIN_LIBVIRT_MEMPAGES_VERSION = (1, 2, 8)
+# libvirt memory allocation policy for each guest NUMA node
+MIN_LIBVIRT_MEMNODE_VERSION = (1, 2, 7)
 
 # Hyper-V paravirtualized time source
 MIN_LIBVIRT_HYPERV_TIMER_VERSION = (1, 2, 2)
@@ -3481,14 +3483,14 @@ def _get_guest_numa_config(self, instance_numa_topology, flavor,
                 guest_cpu_tune.vcpupin.sort(key=operator.attrgetter("id"))
 
                 guest_numa_tune.memory = numa_mem
-                guest_numa_tune.memnodes = numa_memnodes
 
                 # normalize cell.id
-                for i, (cell, memnode) in enumerate(
-                                            zip(guest_cpu_numa_config.cells,
-                                                guest_numa_tune.memnodes)):
+                for i, cell in enumerate(guest_cpu_numa_config.cells):
                     cell.id = i
-                    memnode.cellid = i
+
+                guest_numa_tune.memnodes = self._get_guest_numa_tune_memnodes(
+                                                        guest_cpu_numa_config,
+                                                        numa_memnodes)
 
                 return GuestNumaConfig(None, guest_cpu_tune,
                                        guest_cpu_numa_config,
@@ -3497,6 +3499,18 @@ def _get_guest_numa_config(self, instance_numa_topology, flavor,
                 return GuestNumaConfig(allowed_cpus, None,
                                        guest_cpu_numa_config, None)
 
+    def _get_guest_numa_tune_memnodes(self, guest_cpu_numa_config,
+                                      numa_memnodes):
+        if not self._host.has_min_version(MIN_LIBVIRT_MEMNODE_VERSION):
+            return
+
+        # normalize cell.id
+        for (cell, memnode) in zip(guest_cpu_numa_config.cells,
+                                    numa_memnodes):
+            memnode.cellid = cell.id
+
+        return numa_memnodes
+
     def _get_guest_os_type(self, virt_type):
         """Returns the guest OS type based on virt type."""
         if virt_type == "lxc":