Enable and use COMPUTE_ACCELERATORS trait.

For description, see https://review.opendev.org/#/c/698961.

Change-Id: I324adf88e54ce09c13ca2dbe638905769806d81b
Blueprint: nova-cyborg-interaction

lower-constraints.txt

@@ -66,7 +66,7 @@ os-brick==2.6.2
 os-client-config==1.29.0
 os-resource-classes==0.4.0
 os-service-types==1.7.0
-os-traits==2.1.0
+os-traits==2.2.0
 os-vif==1.14.0
 os-win==3.0.0
 os-xenapi==0.3.3

nova/scheduler/request_filter.py

@@ -250,6 +250,22 @@ def compute_status_filter(ctxt, request_spec):
     return True
 
 
+@trace_request_filter
+def accelerators_filter(ctxt, request_spec):
+    """Allow only compute nodes with accelerator support.
+
+    This filter retains only nodes whose compute manager published the
+    COMPUTE_ACCELERATORS trait, thus indicating the version of n-cpu is
+    sufficient to handle accelerator requests.
+    """
+    trait_name = os_traits.COMPUTE_ACCELERATORS
+    if request_spec.flavor.extra_specs.get('accel:device_profile'):
+        request_spec.root_required.add(trait_name)
+        LOG.debug('accelerators_filter request filter added required '
+                  'trait %s', trait_name)
+    return True
+
+
 ALL_REQUEST_FILTERS = [
     require_tenant_aggregate,
     map_az_to_placement_aggregate,
@@ -257,6 +273,7 @@ ALL_REQUEST_FILTERS = [
     compute_status_filter,
     isolate_aggregates,
     transform_image_metadata,
+    accelerators_filter,
 ]
 
 

nova/tests/functional/integrated_helpers.py

@@ -445,6 +445,7 @@ class ProviderUsageBaseTestCase(test.TestCase, InstanceHelperMixin):
     # nova.virt.libvirt.driver.LibvirtDriver.capabilities
     expected_libvirt_driver_capability_traits = set([
         six.u(trait) for trait in [
+            os_traits.COMPUTE_ACCELERATORS,
             os_traits.COMPUTE_DEVICE_TAGGING,
             os_traits.COMPUTE_NET_ATTACH_INTERFACE,
             os_traits.COMPUTE_NET_ATTACH_INTERFACE_WITH_TAG,
@@ -464,6 +465,7 @@ class ProviderUsageBaseTestCase(test.TestCase, InstanceHelperMixin):
     # nova.virt.fake.FakeDriver.capabilities
     expected_fake_driver_capability_traits = set([
         six.u(trait) for trait in [
+            os_traits.COMPUTE_ACCELERATORS,
             os_traits.COMPUTE_IMAGE_TYPE_RAW,
             os_traits.COMPUTE_DEVICE_TAGGING,
             os_traits.COMPUTE_NET_ATTACH_INTERFACE,

nova/tests/unit/scheduler/test_request_filter.py

@@ -435,3 +435,42 @@ class TestRequestFilter(test.NoDBTestCase):
             request_filter.transform_image_metadata(self.context, reqspec)
         )
         self.assertEqual(set(), reqspec.root_required)
+
+    @mock.patch.object(request_filter, 'LOG')
+    def test_accelerators_filter_with_device_profile(self, mock_log):
+        # First ensure that accelerators_filter is included
+        self.assertIn(request_filter.accelerators_filter,
+                      request_filter.ALL_REQUEST_FILTERS)
+
+        es = {'accel:device_profile': 'mydp'}
+        reqspec = objects.RequestSpec(flavor=objects.Flavor(extra_specs=es))
+        self.assertEqual(set(), reqspec.root_required)
+        self.assertEqual(set(), reqspec.root_forbidden)
+
+        # Request filter puts the trait into the request spec
+        request_filter.accelerators_filter(self.context, reqspec)
+        self.assertEqual({ot.COMPUTE_ACCELERATORS}, reqspec.root_required)
+        self.assertEqual(set(), reqspec.root_forbidden)
+
+        # Assert both the in-method logging and trace decorator.
+        log_lines = [c[0][0] for c in mock_log.debug.call_args_list]
+        self.assertIn('added required trait', log_lines[0])
+        self.assertIn('took %.1f seconds', log_lines[1])
+
+    @mock.patch.object(request_filter, 'LOG')
+    def test_accelerators_filter_no_device_profile(self, mock_log):
+        # First ensure that accelerators_filter is included
+        self.assertIn(request_filter.accelerators_filter,
+                      request_filter.ALL_REQUEST_FILTERS)
+
+        reqspec = objects.RequestSpec(flavor=objects.Flavor(extra_specs={}))
+        self.assertEqual(set(), reqspec.root_required)
+        self.assertEqual(set(), reqspec.root_forbidden)
+
+        # Request filter puts the trait into the request spec
+        request_filter.accelerators_filter(self.context, reqspec)
+        self.assertEqual(set(), reqspec.root_required)
+        self.assertEqual(set(), reqspec.root_forbidden)
+
+        # Assert about logging
+        mock_log.assert_not_called()

nova/virt/driver.py

@@ -110,6 +110,7 @@ CAPABILITY_TRAITS_MAP = {
     "supports_multiattach": os_traits.COMPUTE_VOLUME_MULTI_ATTACH,
     # Added in os-traits 0.8.0.
     "supports_trusted_certs": os_traits.COMPUTE_TRUSTED_CERTS,
+    "supports_accelerators": os_traits.COMPUTE_ACCELERATORS,
 
     # Image type support flags, added in os-traits 0.12.0
     "supports_image_type_aki": os_traits.COMPUTE_IMAGE_TYPE_AKI,
@@ -176,6 +177,7 @@ class ComputeDriver(object):
         "supports_multiattach": False,
         "supports_trusted_certs": False,
         "supports_pcpus": False,
+        "supports_accelerators": False,
 
         # Image type support flags
         "supports_image_type_aki": False,

nova/virt/fake.py

@@ -113,6 +113,7 @@ class FakeDriver(driver.ComputeDriver):
         "supports_multiattach": True,
         "supports_trusted_certs": True,
         "supports_pcpus": False,
+        "supports_accelerators": True,
 
         # Supported image types
         "supports_image_type_raw": True,

nova/virt/hyperv/driver.py

@@ -101,6 +101,7 @@ class HyperVDriver(driver.ComputeDriver):
         "supports_multiattach": False,
         "supports_trusted_certs": False,
         "supports_pcpus": False,
+        "supports_accelerators": False,
 
         # Supported image types
         "supports_image_type_vhd": True,

nova/virt/ironic/driver.py

@@ -163,6 +163,7 @@ class IronicDriver(virt_driver.ComputeDriver):
         "supports_multiattach": False,
         "supports_trusted_certs": False,
         "supports_pcpus": False,
+        "supports_accelerators": False,
 
         # Image type support flags
         "supports_image_type_aki": False,

nova/virt/libvirt/driver.py

@@ -332,6 +332,7 @@ class LibvirtDriver(driver.ComputeDriver):
             "supports_image_type_qcow2": not requires_raw_image,
             "supports_image_type_ploop": requires_ploop_image,
             "supports_pcpus": True,
+            "supports_accelerators": True,
         }
         super(LibvirtDriver, self).__init__(virtapi)
 

nova/virt/powervm/driver.py

@@ -78,6 +78,7 @@ class PowerVMDriver(driver.ComputeDriver):
             'supports_multiattach': False,
             'supports_trusted_certs': False,
             'supports_pcpus': False,
+            "supports_accelerators": False,
 
             # Supported image types
             "supports_image_type_aki": False,

nova/virt/vmwareapi/driver.py

@@ -70,6 +70,7 @@ class VMwareVCDriver(driver.ComputeDriver):
         "supports_multiattach": False,
         "supports_trusted_certs": False,
         "supports_pcpus": False,
+        "supports_accelerators": False,
 
         # Image type support flags
         "supports_image_type_aki": False,

nova/virt/xenapi/driver.py

@@ -70,6 +70,7 @@ class XenAPIDriver(driver.ComputeDriver):
         "supports_multiattach": False,
         "supports_trusted_certs": False,
         "supports_pcpus": False,
+        "supports_accelerators": False,
 
         # Image type support flags
         "supports_image_type_aki": False,

requirements.txt

@@ -55,7 +55,7 @@ psutil>=3.2.2 # BSD
 oslo.versionedobjects>=1.35.0 # Apache-2.0
 os-brick>=2.6.2 # Apache-2.0
 os-resource-classes>=0.4.0 # Apache-2.0
-os-traits>=2.1.0 # Apache-2.0
+os-traits>=2.2.0 # Apache-2.0
 os-vif>=1.14.0 # Apache-2.0
 os-win>=3.0.0 # Apache-2.0
 castellan>=0.16.0 # Apache-2.0