Throw exception if numa_nodes is not set to integer greater than 0

As [1] is abandoned, I used that patchset to create a new one.
This patchset is freshened to the current master branch.

This patch introduces InvalidNUMANodesNumber exception, which is
thrown when trying to boot an instance with a flavor that has
hw:numa_nodes=0 extra spec set. That means that NUMA nodes is set to 0,
which is incorrect.

[1]: https://review.openstack.org/#/c/190267

Change-Id: I6bd8f69e582c537a5fec40064638a8887a08cac4
Co-Authored-By: Karim Boumedhel <karimboumedhel@gmail.com>
Closes-Bug: #1402709

nova/api/openstack/compute/servers.py

@@ -689,6 +689,7 @@ class ServersController(wsgi.Controller):
                 exception.ImageNUMATopologyCPUDuplicates,
                 exception.ImageNUMATopologyCPUsUnassigned,
                 exception.ImageNUMATopologyMemoryOutOfRange,
+                exception.InvalidNUMANodesNumber,
                 exception.InstanceGroupNotFound,
                 exception.PciRequestAliasNotDefined,
                 exception.SnapshotNotFound,

nova/exception.py

@@ -372,6 +372,11 @@ class InvalidStrTime(Invalid):
     msg_fmt = _("Invalid datetime string: %(reason)s")
 
 
+class InvalidNUMANodesNumber(Invalid):
+    msg_fmt = _("The property 'numa_nodes' cannot be '%(nodes)s'. "
+                "It must be a number greater than 0")
+
+
 class InvalidName(Invalid):
     msg_fmt = _("An invalid 'name' value was provided. "
                 "The name must be: %(reason)s")

nova/tests/unit/api/openstack/compute/test_serversV21.py

@@ -3255,6 +3255,14 @@ class ServersControllerCreateTest(test.TestCase):
                           self.controller.create,
                           self.req, body=self.body)
 
+    @mock.patch.object(compute_api.API, 'create',
+                       side_effect=exception.InvalidNUMANodesNumber(
+                           details=''))
+    def test_create_instance_raise_invalid_numa_nodes(self, mock_create):
+        self.assertRaises(webob.exc.HTTPBadRequest,
+                          self.controller.create,
+                          self.req, body=self.body)
+
     @mock.patch.object(compute_api.API, 'create',
                        side_effect=exception.InvalidBDMFormat(details=''))
     def test_create_instance_raise_invalid_bdm_format(self, mock_create):

nova/tests/unit/virt/test_hardware.py

@@ -856,6 +856,36 @@ class NUMATopologyTest(test.NoDBTestCase):
                             memory=2048, pagesize=2048)
                     ]),
             },
+            {
+                # a nodes number of zero should lead to an
+                # exception
+                "flavor": objects.Flavor(vcpus=8, memory_mb=2048, extra_specs={
+                    "hw:numa_nodes": 0
+                }),
+                "image": {
+                },
+                "expect": exception.InvalidNUMANodesNumber,
+            },
+            {
+                # a negative nodes number should lead to an
+                # exception
+                "flavor": objects.Flavor(vcpus=8, memory_mb=2048, extra_specs={
+                    "hw:numa_nodes": -1
+                }),
+                "image": {
+                },
+                "expect": exception.InvalidNUMANodesNumber,
+            },
+            {
+                # a nodes number not numeric should lead to an
+                # exception
+                "flavor": objects.Flavor(vcpus=8, memory_mb=2048, extra_specs={
+                    "hw:numa_nodes": 'x'
+                }),
+                "image": {
+                },
+                "expect": exception.InvalidNUMANodesNumber,
+            },
             {
                 # vcpus is not a multiple of nodes, so it
                 # is an error to not provide cpu/mem mapping

nova/virt/hardware.py

@@ -1178,6 +1178,18 @@ def _add_cpu_pinning_constraint(flavor, image_meta, numa_topology):
     return numa_topology
 
 
+def _validate_numa_nodes(nodes):
+    """Validate NUMA nodes number
+
+    :param nodes: The number of NUMA nodes
+    :raises: exception.InvalidNUMANodesNumber if the given
+             parameter is not a number or less than 1
+    """
+    if nodes is not None and (not strutils.is_int_like(nodes) or
+       int(nodes) < 1):
+        raise exception.InvalidNUMANodesNumber(nodes=nodes)
+
+
 # TODO(sahid): Move numa related to hardward/numa.py
 def numa_get_constraints(flavor, image_meta):
     """Return topology related to input request
@@ -1189,6 +1201,8 @@ def numa_get_constraints(flavor, image_meta):
     image properties are not correctly specified, or
     exception.ImageNUMATopologyForbidden if an attempt is
     made to override flavor settings with image properties.
+    exception.InvalidNUMANodesNumber if the number of NUMA
+    nodes is less than 1 (or not an integer).
 
     :returns: InstanceNUMATopology or None
     """
@@ -1196,12 +1210,14 @@ def numa_get_constraints(flavor, image_meta):
     nodes = flavor.get('extra_specs', {}).get("hw:numa_nodes")
     props = image_meta.properties
     if nodes is not None:
+        _validate_numa_nodes(nodes)
         if props.obj_attr_is_set("hw_numa_nodes"):
             raise exception.ImageNUMATopologyForbidden(
                 name='hw_numa_nodes')
         nodes = int(nodes)
     else:
         nodes = props.get("hw_numa_nodes")
+        _validate_numa_nodes(nodes)
 
     pagesize = _numa_get_pagesize_constraints(
         flavor, image_meta)