Allow scheduler manager NoValidHost exception to pass over RPC

Calls to scheduler.manager.select_hosts are expected to throw NoValidHost
exceptions if no hosts match such requests. For the exception to be passed
over RPC, the method must be decorated with:

@rpc_common.client_exceptions(exception.NoValidHost)

Resolves bug 1192693.

Change-Id: If9d1f15ff1239e422067893f9d837c41e5f5474d

2 files changed, 12 insertions, 0 deletions

diff --git a/nova/scheduler/manager.py b/nova/scheduler/manager.py
index 9429a0662..fee29768a 100644
--- a/nova/scheduler/manager.py
+++ b/nova/scheduler/manager.py
@@ -308,6 +308,7 @@ class SchedulerManager(manager.Manager):
     def get_backdoor_port(self, context):
         return self.backdoor_port
 
+    @rpc_common.client_exceptions(exception.NoValidHost)
     def select_hosts(self, context, request_spec, filter_properties):
         """Returns host(s) best suited for this request_spec
         and filter_properties.
diff --git a/nova/tests/scheduler/test_scheduler.py b/nova/tests/scheduler/test_scheduler.py
index 0574f6d2e..d627f2765 100644
--- a/nova/tests/scheduler/test_scheduler.py
+++ b/nova/tests/scheduler/test_scheduler.py
@@ -402,6 +402,17 @@ class SchedulerManagerTestCase(test.NoDBTestCase):
         self.manager._set_vm_state_and_notify('foo', {'vm_state': 'foo'},
                                               self.context, None, request)
 
+    def test_select_hosts_throws_rpc_clientexception(self):
+        self.mox.StubOutWithMock(self.manager.driver, 'select_hosts')
+
+        self.manager.driver.select_hosts(self.context, {}, {}).AndRaise(
+                exception.NoValidHost(reason=""))
+
+        self.mox.ReplayAll()
+        self.assertRaises(rpc_common.ClientException,
+                          self.manager.select_hosts,
+                          self.context, {}, {})
+
 
 class SchedulerTestCase(test.NoDBTestCase):
     """Test case for base scheduler driver class."""