Make ComputeFilter verify compute-related instance properties

This change adds checks in the ComputeFilter to verify compute hosts can
support the (architecture, hypervisor_type, vm_mode) triple specified
in the instance properties, improving support for heterogeneous clouds.

Images can be marked with the architecture, hypervisor, and virtual
machine mode they require, e.g.

glance image-update --property architecture=x86_64 \
  --property hypervisor_type=kvm <image-uuid>
glance image-update --property architecture=i686 \
  --property hypervisor_type=xen --property vm_mode=xen <image-uuid>
glance image-update --property architecture=x86_64 \
  --property hypervisor_type=xen --property vm_mode=hvm <image-uuid>

These properties are included in the request_spec part of the run_instance
RPC message and made available to the ComputeFilter.  The ComputeFilter
will only pass compute nodes that satisfy the specified properties.
If no properties are specified, the ComputeFilter behavior is unchanged.

Adding these checks to the compute filter seems consistent with its
definition [1]:

"ComputeFilter - checks that the capabilities provided by the compute
service satisfy the extra specifications, associated with the instance
type."

[1] https://github.com/openstack/nova/blob/master/doc/source/devref/filter_scheduler.rst

DocImpact

Change-Id: I993f2e222ec036f1045f3cc5cc1851e730962729

2 files changed, 155 insertions, 2 deletions

diff --git a/nova/scheduler/filters/compute_filter.py b/nova/scheduler/filters/compute_filter.py
index 2d7c898d6..c0ee98762 100644
--- a/nova/scheduler/filters/compute_filter.py
+++ b/nova/scheduler/filters/compute_filter.py
@@ -22,10 +22,59 @@ LOG = logging.getLogger(__name__)
 
 
 class ComputeFilter(filters.BaseHostFilter):
-    """Filter on active Compute nodes"""
+    """Filter on active Compute nodes that satisfy the instance properties"""
+
+    def _instance_supported(self, capabilities, instance_meta):
+        """Check if the instance is supported by the hypervisor.
+
+        The instance may specify an architecture, hypervisor, and
+        vm_mode, e.g. (x86_64, kvm, hvm).
+        """
+        inst_arch = instance_meta.get('image_architecture', None)
+        inst_h_type = instance_meta.get('image_hypervisor_type', None)
+        inst_vm_mode = instance_meta.get('image_vm_mode', None)
+        inst_props_req = (inst_arch, inst_h_type, inst_vm_mode)
+
+        # Supported if no compute-related instance properties are specified
+        if not any(inst_props_req):
+            return True
+
+        supp_instances = capabilities.get('supported_instances', None)
+        # Not supported if an instance property is requested but nothing
+        # advertised by the host.
+        if not supp_instances:
+            LOG.debug(_("Instance contains properties %(instance_meta)s, "
+                        "but no corresponding capabilities are advertised "
+                        "by the compute node"), locals())
+            return False
+
+        def _compare_props(props, other_props):
+            for i in props:
+                if i and i not in other_props:
+                    return False
+            return True
+
+        for supp_inst in supp_instances:
+            if _compare_props(inst_props_req, supp_inst):
+                LOG.debug(_("Instance properties %(instance_meta)s "
+                            "are satisfied by compute host capabilities "
+                            "%(capabilities)s"), locals())
+                return True
+
+        LOG.debug(_("Instance contains properties %(instance_meta)s "
+                    "that are not provided by the compute node "
+                    "capabilities %(capabilities)s"), locals())
+        return False
 
     def host_passes(self, host_state, filter_properties):
-        """Returns True for only active compute nodes"""
+        """Check if host passes instance compute properties.
+
+        Returns True for active compute nodes that satisfy
+        the compute properties specified in the instance.
+        """
+        spec = filter_properties.get('request_spec', {})
+        instance_props = spec.get('instance_properties', {})
+        instance_meta = instance_props.get('system_metadata', {})
         instance_type = filter_properties.get('instance_type')
         if host_state.topic != 'compute' or not instance_type:
             return True
@@ -40,4 +89,8 @@ class ComputeFilter(filters.BaseHostFilter):
             LOG.debug(_("%(host_state)s is disabled via capabilities"),
                     locals())
             return False
+        if not self._instance_supported(capabilities, instance_meta):
+            LOG.debug(_("%(host_state)s does not support requested "
+                        "instance_properties"), locals())
+            return False
         return True
diff --git a/nova/tests/scheduler/test_host_filters.py b/nova/tests/scheduler/test_host_filters.py
index ca5ca5366..227fbfa82 100644
--- a/nova/tests/scheduler/test_host_filters.py
+++ b/nova/tests/scheduler/test_host_filters.py
@@ -394,6 +394,106 @@ class HostFiltersTestCase(test.TestCase):
                  'service': service})
         self.assertTrue(filt_cls.host_passes(host, filter_properties))
 
+    def test_compute_filter_passes_same_inst_props(self):
+        self._stub_service_is_up(True)
+        filt_cls = self.class_map['ComputeFilter']()
+        inst_meta = {'system_metadata': {'image_architecture': 'x86_64',
+                                         'image_hypervisor_type': 'kvm',
+                                         'image_vm_mode': 'hvm'}}
+        req_spec = {'instance_properties': inst_meta}
+        filter_properties = {'instance_type': {'memory_mb': 1024},
+                             'request_spec': req_spec}
+        capabilities = {'enabled': True,
+                            'supported_instances': [
+                                ('x86_64', 'kvm', 'hvm')]}
+        service = {'disabled': False}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024, 'capabilities': capabilities,
+                 'service': service})
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+    def test_compute_filter_fails_different_inst_props(self):
+        self._stub_service_is_up(True)
+        filt_cls = self.class_map['ComputeFilter']()
+        inst_meta = {'system_metadata': {'image_architecture': 'arm',
+                                         'image_hypervisor_type': 'qemu',
+                                         'image_vm_mode': 'hvm'}}
+        req_spec = {'instance_properties': inst_meta}
+        filter_properties = {'instance_type': {'memory_mb': 1024},
+                             'request_spec': req_spec}
+        capabilities = {'enabled': True,
+                            'supported_instances': [
+                                ('x86_64', 'kvm', 'hvm')]}
+        service = {'disabled': False}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024, 'capabilities': capabilities,
+                 'service': service})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+    def test_compute_filter_passes_partial_inst_props(self):
+        self._stub_service_is_up(True)
+        filt_cls = self.class_map['ComputeFilter']()
+        inst_meta = {'system_metadata': {'image_architecture': 'x86_64',
+                                         'image_vm_mode': 'hvm'}}
+        req_spec = {'instance_properties': inst_meta}
+        filter_properties = {'instance_type': {'memory_mb': 1024},
+                             'request_spec': req_spec}
+        capabilities = {'enabled': True,
+                            'supported_instances': [
+                                ('x86_64', 'kvm', 'hvm')]}
+        service = {'disabled': False}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024, 'capabilities': capabilities,
+                 'service': service})
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+    def test_compute_filter_fails_partial_inst_props(self):
+        self._stub_service_is_up(True)
+        filt_cls = self.class_map['ComputeFilter']()
+        inst_meta = {'system_metadata': {'image_architecture': 'x86_64',
+                                         'image_vm_mode': 'hvm'}}
+        req_spec = {'instance_properties': inst_meta}
+        filter_properties = {'instance_type': {'memory_mb': 1024},
+                             'request_spec': req_spec}
+        capabilities = {'enabled': True,
+                            'supported_instances': [
+                                ('x86_64', 'xen', 'xen')]}
+        service = {'disabled': False}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024, 'capabilities': capabilities,
+                 'service': service})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+    def test_compute_filter_passes_without_inst_props(self):
+        self._stub_service_is_up(True)
+        filt_cls = self.class_map['ComputeFilter']()
+        filter_properties = {'instance_type': {'memory_mb': 1024},
+                             'request_spec': {}}
+        capabilities = {'enabled': True,
+                            'supported_instances': [
+                                ('x86_64', 'kvm', 'hvm')]}
+        service = {'disabled': False}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024, 'capabilities': capabilities,
+                 'service': service})
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+    def test_compute_filter_fails_without_host_props(self):
+        self._stub_service_is_up(True)
+        filt_cls = self.class_map['ComputeFilter']()
+        inst_meta = {'system_metadata': {'image_architecture': 'x86_64',
+                                         'image_hypervisor_type': 'kvm',
+                                         'image_vm_mode': 'hvm'}}
+        req_spec = {'instance_properties': inst_meta}
+        filter_properties = {'instance_type': {'memory_mb': 1024},
+                             'request_spec': req_spec}
+        capabilities = {'enabled': True}
+        service = {'disabled': False}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024, 'capabilities': capabilities,
+                 'service': service})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
     def test_compute_filter_passes_extra_specs_noop(self):
         self._stub_service_is_up(True)
         filt_cls = self.class_map['ComputeCapabilitiesFilter']()