Add option to force hosts to scheduler

Change-Id: I7364115e247ebeb441fa838ac66db5ef5f608b55

nova/flags.py

@@ -467,3 +467,5 @@ DEFINE_boolean('allow_ec2_admin_api', False, 'Enable/Disable EC2 Admin API')
 
 DEFINE_integer('service_down_time', 60,
         'maximum time since last check-in for up service')
+DEFINE_string('default_schedule_zone', None,
+              'zone to use when user doesnt specify one')

nova/scheduler/host_manager.py

@@ -117,6 +117,9 @@ class HostState(object):
 
         if self.host in filter_properties.get('ignore_hosts', []):
             return False
+        force_hosts = filter_properties.get('force_hosts', [])
+        if force_hosts:
+            return self.host in force_hosts
         for filter_fn in filter_fns:
             if not filter_fn(self, filter_properties):
                 return False

nova/scheduler/simple.py

@@ -35,8 +35,6 @@ flags.DEFINE_integer("max_gigabytes", 10000,
                      "maximum number of volume gigabytes to allow per host")
 flags.DEFINE_integer("max_networks", 1000,
                      "maximum number of networks to allow per host")
-flags.DEFINE_string('default_schedule_zone', None,
-                    'zone to use when user doesnt specify one')
 flags.DEFINE_list('isolated_images', [], 'Images to run on isolated host')
 flags.DEFINE_list('isolated_hosts', [], 'Host reserved for specific images')
 flags.DEFINE_boolean('skip_isolated_core_check', True,

nova/tests/scheduler/test_host_manager.py

@@ -18,8 +18,6 @@ Tests For HostManager
 
 import datetime
 
-import mox
-
 from nova import db
 from nova import exception
 from nova import log as logging
@@ -364,3 +362,21 @@ class HostStateTestCase(test.TestCase):
         result = fake_host.passes_filters(filter_fns, filter_properties)
         self.mox.VerifyAll()
         self.assertFalse(result)
+
+    def test_host_state_passes_filters_skipped_from_force(self):
+        fake_host = host_manager.HostState('host1', 'compute')
+        filter_properties = {'force_hosts': ['host1']}
+
+        cls1 = ComputeFilterClass1()
+        cls2 = ComputeFilterClass2()
+        self.mox.StubOutWithMock(cls1, 'host_passes')
+        self.mox.StubOutWithMock(cls2, 'host_passes')
+        filter_fns = [cls1.host_passes, cls2.host_passes]
+
+        # cls[12].host_passes() not called because of short circuit
+        # with matching host to force
+
+        self.mox.ReplayAll()
+        result = fake_host.passes_filters(filter_fns, filter_properties)
+        self.mox.VerifyAll()
+        self.assertTrue(result)