Merge "Define "supported_instances" for fake compute"

doc/source/devref/development.environment.rst

@@ -143,7 +143,7 @@ basis by running::
      $ tools/with_venv.sh <your command>
 
 Using a remote debugger
-----------------------
+-----------------------
 
 Some modern IDE such as pycharm (commercial) or Eclipse (open source) support remote debugging.  In order to run nova with remote debugging, start the nova process
 with the following parameters
@@ -156,6 +156,26 @@ For Eclipse - http://pydev.org/manual_adv_remote_debugger.html
 
 More detailed instructions are located here - http://novaremotedebug.blogspot.com
 
+Using fake computes for tests
+-----------------------------
+
+The number of instances supported by fake computes is not limited by physical
+constraints. It allows to perform stress tests on a deployment with few
+resources (typically a laptop). But you must avoid using scheduler filters
+limiting the number of instances per compute (like RamFilter, DiskFilter,
+AggregateCoreFilter), otherwise they will limit the number of instances per
+compute.
+
+
+Fake computes can also be used in multi hypervisor-type deployments in order to
+take advantage of fake and "real" computes during tests:
+
+* create many fake instances for stress tests
+* create some "real" instances for functional tests
+
+Fake computes can be used for testing Nova itself but also applications on top
+of it.
+
 Contributing Your Work
 ----------------------
 

nova/tests/virt/test_virt_drivers.py

@@ -26,6 +26,7 @@ import six
 from nova.compute import manager
 from nova import exception
 from nova.openstack.common import importutils
+from nova.openstack.common import jsonutils
 from nova.openstack.common import log as logging
 from nova import test
 from nova.tests.image import fake as fake_image
@@ -567,7 +568,8 @@ class _VirtDriverTestCase(_FakeDriverBackendTestCase):
     def _check_available_resource_fields(self, host_status):
         keys = ['vcpus', 'memory_mb', 'local_gb', 'vcpus_used',
                 'memory_mb_used', 'hypervisor_type', 'hypervisor_version',
-                'hypervisor_hostname', 'cpu_info', 'disk_available_least']
+                'hypervisor_hostname', 'cpu_info', 'disk_available_least',
+                'supported_instances']
         for key in keys:
             self.assertIn(key, host_status)
 
@@ -707,6 +709,19 @@ class FakeConnectionTestCase(_VirtDriverTestCase, test.TestCase):
         fake.set_nodes(['myhostname'])
         super(FakeConnectionTestCase, self).setUp()
 
+    def _check_available_resource_fields(self, host_status):
+        super(FakeConnectionTestCase, self)._check_available_resource_fields(
+            host_status)
+
+        hypervisor_type = host_status['hypervisor_type']
+        supported_instances = host_status['supported_instances']
+        try:
+            # supported_instances could be JSON wrapped
+            supported_instances = jsonutils.loads(supported_instances)
+        except TypeError:
+            pass
+        self.assertTrue(any(hypervisor_type in x for x in supported_instances))
+
 
 class LibvirtConnTestCase(_VirtDriverTestCase, test.TestCase):
     def setUp(self):

nova/virt/fake.py

@@ -33,6 +33,7 @@ from nova.compute import task_states
 from nova import db
 from nova import exception
 from nova.openstack.common.gettextutils import _
+from nova.openstack.common import jsonutils
 from nova.openstack.common import log as logging
 from nova import utils
 from nova.virt import driver
@@ -103,6 +104,7 @@ class FakeDriver(driver.ComputeDriver):
           'hypervisor_hostname': CONF.host,
           'cpu_info': {},
           'disk_available_least': 500000000000,
+          'supported_instances': [(None, 'fake', None)],
           }
         self._mounts = {}
         self._interfaces = {}
@@ -360,7 +362,9 @@ class FakeDriver(driver.ComputeDriver):
                'hypervisor_version': '1.0',
                'hypervisor_hostname': nodename,
                'disk_available_least': 0,
-               'cpu_info': '?'}
+               'cpu_info': '?',
+               'supported_instances': jsonutils.dumps([(None, 'fake', None)])
+              }
         return dic
 
     def ensure_filtering_rules_for_instance(self, instance_ref, network_info):