Extract live-migration scheduler logic from the scheduler driver

Before moving the control of live-migration into the conductor,
extract the live-migration control logic into a separate class.

The callback to select_hosts will be replaced by a new
scheduler rpc method in a later changeset.

Part of blueprint live-migration-to-conductor
Change-Id: I6de33ada6dc377e20f8df07da92244f2c150b9fe

2 files changed, 322 insertions, 0 deletions

diff --git a/nova/tests/conductor/tasks/__init__.py b/nova/tests/conductor/tasks/__init__.py
new file mode 100644
index 000000000..94e731d20
--- /dev/null
+++ b/nova/tests/conductor/tasks/__init__.py
@@ -0,0 +1,11 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
diff --git a/nova/tests/conductor/tasks/test_live_migrate.py b/nova/tests/conductor/tasks/test_live_migrate.py
new file mode 100644
index 000000000..c54e53b1a
--- /dev/null
+++ b/nova/tests/conductor/tasks/test_live_migrate.py
@@ -0,0 +1,311 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from nova.compute import flavors
+from nova.compute import power_state
+from nova.conductor.tasks import live_migrate
+from nova import db
+from nova import exception
+from nova import test
+
+
+class LiveMigrationTaskTestCase(test.TestCase):
+    def setUp(self):
+        super(LiveMigrationTaskTestCase, self).setUp()
+        self.context = "context"
+        self.instance_host = "host"
+        self.instance_uuid = "uuid"
+        self.instance_image = "image_ref"
+        self.instance = {
+            "host": self.instance_host,
+            "uuid": self.instance_uuid,
+            "power_state": power_state.RUNNING,
+            "memory_mb": 512,
+            "image_ref": self.instance_image}
+        self.destination = "destination"
+        self.block_migration = "bm"
+        self.disk_over_commit = "doc"
+        self.select_hosts_callback = self._select_hosts_callback
+        self._generate_task()
+
+    def _generate_task(self):
+        self.task = live_migrate.LiveMigrationTask(self.context,
+            self.instance, self.destination, self.block_migration,
+            self.disk_over_commit, self.select_hosts_callback)
+
+    def _select_hosts_callback(self, *args):
+        return ["host1"]
+
+    def test_execute_with_destination(self):
+        self.mox.StubOutWithMock(self.task, '_check_host_is_up')
+        self.mox.StubOutWithMock(self.task, '_check_requested_destination')
+        self.mox.StubOutWithMock(self.task.compute_rpcapi, 'live_migration')
+
+        self.task._check_host_is_up(self.instance_host)
+        self.task._check_requested_destination()
+        self.task.compute_rpcapi.live_migration(self.context,
+                host=self.instance_host,
+                instance=self.instance,
+                dest=self.destination,
+                block_migration=self.block_migration,
+                migrate_data=None).AndReturn("bob")
+
+        self.mox.ReplayAll()
+        self.assertEqual("bob", self.task.execute())
+
+    def test_execute_without_destination(self):
+        self.destination = None
+        self._generate_task()
+        self.assertEqual(None, self.task.destination)
+
+        self.mox.StubOutWithMock(self.task, '_check_host_is_up')
+        self.mox.StubOutWithMock(self.task, '_find_destination')
+        self.mox.StubOutWithMock(self.task.compute_rpcapi, 'live_migration')
+
+        self.task._check_host_is_up(self.instance_host)
+        self.task._find_destination().AndReturn("found_host")
+        self.task.compute_rpcapi.live_migration(self.context,
+                host=self.instance_host,
+                instance=self.instance,
+                dest="found_host",
+                block_migration=self.block_migration,
+                migrate_data=None).AndReturn("bob")
+
+        self.mox.ReplayAll()
+        self.assertEqual("bob", self.task.execute())
+
+    def test_check_instance_is_running_passes(self):
+        self.task._check_instance_is_running()
+
+    def test_check_instance_is_running_fails_when_shutdown(self):
+        self.task.instance['power_state'] = power_state.SHUTDOWN
+        self.assertRaises(exception.InstanceNotRunning,
+                          self.task._check_instance_is_running)
+
+    def test_check_instance_host_is_up(self):
+        self.mox.StubOutWithMock(db, 'service_get_by_compute_host')
+        self.mox.StubOutWithMock(self.task.servicegroup_api, 'service_is_up')
+
+        db.service_get_by_compute_host(self.context,
+                                       "host").AndReturn("service")
+        self.task.servicegroup_api.service_is_up("service").AndReturn(True)
+
+        self.mox.ReplayAll()
+        self.task._check_host_is_up("host")
+
+    def test_check_instance_host_is_up_fails_if_not_up(self):
+        self.mox.StubOutWithMock(db, 'service_get_by_compute_host')
+        self.mox.StubOutWithMock(self.task.servicegroup_api, 'service_is_up')
+
+        db.service_get_by_compute_host(self.context,
+                                       "host").AndReturn("service")
+        self.task.servicegroup_api.service_is_up("service").AndReturn(False)
+
+        self.mox.ReplayAll()
+        self.assertRaises(exception.ComputeServiceUnavailable,
+                self.task._check_host_is_up, "host")
+
+    def test_check_instance_host_is_up_fails_if_not_found(self):
+        self.mox.StubOutWithMock(db, 'service_get_by_compute_host')
+
+        db.service_get_by_compute_host(self.context,
+                                       "host").AndRaise(exception.NotFound)
+
+        self.mox.ReplayAll()
+        self.assertRaises(exception.ComputeServiceUnavailable,
+            self.task._check_host_is_up, "host")
+
+    def test_check_requested_destination(self):
+        self.mox.StubOutWithMock(db, 'service_get_by_compute_host')
+        self.mox.StubOutWithMock(self.task, '_get_compute_info')
+        self.mox.StubOutWithMock(self.task.servicegroup_api, 'service_is_up')
+        self.mox.StubOutWithMock(self.task.compute_rpcapi,
+                                 'check_can_live_migrate_destination')
+
+        db.service_get_by_compute_host(self.context,
+                                       self.destination).AndReturn("service")
+        self.task.servicegroup_api.service_is_up("service").AndReturn(True)
+        hypervisor_details = {
+            "hypervisor_type": "a",
+            "hypervisor_version": 6.1,
+            "free_ram_mb": 513
+        }
+        self.task._get_compute_info(self.destination)\
+                .AndReturn(hypervisor_details)
+        self.task._get_compute_info(self.instance_host)\
+                .AndReturn(hypervisor_details)
+        self.task._get_compute_info(self.destination)\
+                .AndReturn(hypervisor_details)
+
+        self.task.compute_rpcapi.check_can_live_migrate_destination(
+                self.context, self.instance, self.destination,
+                self.block_migration, self.disk_over_commit).AndReturn(
+                        "migrate_data")
+
+        self.mox.ReplayAll()
+        self.task._check_requested_destination()
+        self.assertEqual("migrate_data", self.task.migrate_data)
+
+    def test_check_requested_destination_fails_with_same_dest(self):
+        self.task.destination = "same"
+        self.task.source = "same"
+        self.assertRaises(exception.UnableToMigrateToSelf,
+                          self.task._check_requested_destination)
+
+    def test_check_requested_destination_fails_when_destination_is_up(self):
+        self.mox.StubOutWithMock(db, 'service_get_by_compute_host')
+
+        db.service_get_by_compute_host(self.context,
+            self.destination).AndRaise(exception.NotFound)
+
+        self.mox.ReplayAll()
+        self.assertRaises(exception.ComputeServiceUnavailable,
+                          self.task._check_requested_destination)
+
+    def test_check_requested_destination_fails_with_not_enough_memory(self):
+        self.mox.StubOutWithMock(self.task, '_check_host_is_up')
+        self.mox.StubOutWithMock(db, 'service_get_by_compute_host')
+
+        self.task._check_host_is_up(self.destination)
+        db.service_get_by_compute_host(self.context,
+            self.destination).AndReturn({
+                "compute_node": [{"free_ram_mb": 511}]
+            })
+
+        self.mox.ReplayAll()
+        self.assertRaises(exception.MigrationPreCheckError,
+                          self.task._check_requested_destination)
+
+    def test_check_requested_destination_fails_with_hypervisor_diff(self):
+        self.mox.StubOutWithMock(self.task, '_check_host_is_up')
+        self.mox.StubOutWithMock(self.task,
+                '_check_destination_has_enough_memory')
+        self.mox.StubOutWithMock(self.task, '_get_compute_info')
+
+        self.task._check_host_is_up(self.destination)
+        self.task._check_destination_has_enough_memory()
+        self.task._get_compute_info(self.instance_host).AndReturn({
+            "hypervisor_type": "b"
+        })
+        self.task._get_compute_info(self.destination).AndReturn({
+            "hypervisor_type": "a"
+        })
+
+        self.mox.ReplayAll()
+        self.assertRaises(exception.InvalidHypervisorType,
+                          self.task._check_requested_destination)
+
+    def test_check_requested_destination_fails_with_hypervisor_too_old(self):
+        self.mox.StubOutWithMock(self.task, '_check_host_is_up')
+        self.mox.StubOutWithMock(self.task,
+                '_check_destination_has_enough_memory')
+        self.mox.StubOutWithMock(self.task, '_get_compute_info')
+
+        self.task._check_host_is_up(self.destination)
+        self.task._check_destination_has_enough_memory()
+        self.task._get_compute_info(self.instance_host).AndReturn({
+            "hypervisor_type": "a",
+            "hypervisor_version": 7
+        })
+        self.task._get_compute_info(self.destination).AndReturn({
+            "hypervisor_type": "a",
+            "hypervisor_version": 6
+        })
+
+        self.mox.ReplayAll()
+        self.assertRaises(exception.DestinationHypervisorTooOld,
+                          self.task._check_requested_destination)
+
+    def test_find_destination_works(self):
+        self.mox.StubOutWithMock(self.task.image_service, 'show')
+        self.mox.StubOutWithMock(flavors, 'extract_flavor')
+        self.mox.StubOutWithMock(self.task,
+                '_check_compatible_with_source_hypervisor')
+        self.mox.StubOutWithMock(self.task, '_call_livem_checks_on_host')
+
+        self.task.image_service.show(self.context,
+                                     self.instance_image).AndReturn("image")
+        flavors.extract_flavor(self.instance).AndReturn("inst_type")
+        self.task._check_compatible_with_source_hypervisor("host1")
+        self.task._call_livem_checks_on_host("host1")
+
+        self.mox.ReplayAll()
+        self.assertEqual("host1", self.task._find_destination())
+
+    def _test_find_destination_retry_hypervisor_raises(self, error):
+        self.mox.StubOutWithMock(self.task.image_service, 'show')
+        self.mox.StubOutWithMock(flavors, 'extract_flavor')
+        self.mox.StubOutWithMock(self.task,
+                '_check_compatible_with_source_hypervisor')
+        self.mox.StubOutWithMock(self.task, '_call_livem_checks_on_host')
+
+        self.task.image_service.show(self.context,
+                                     self.instance_image).AndReturn("image")
+        flavors.extract_flavor(self.instance).AndReturn("inst_type")
+        self.task._check_compatible_with_source_hypervisor("host1")\
+                .AndRaise(error)
+
+        self.task._check_compatible_with_source_hypervisor("host1")
+        self.task._call_livem_checks_on_host("host1")
+
+        self.mox.ReplayAll()
+        self.assertEqual("host1", self.task._find_destination())
+
+    def test_find_destination_retry_with_old_hypervisor(self):
+        self._test_find_destination_retry_hypervisor_raises(
+                exception.DestinationHypervisorTooOld)
+
+    def test_find_destination_retry_with_invalid_hypervisor_type(self):
+        self._test_find_destination_retry_hypervisor_raises(
+                exception.InvalidHypervisorType)
+
+    def test_find_destination_retry_with_invalid_livem_checks(self):
+        self.mox.StubOutWithMock(self.task.image_service, 'show')
+        self.mox.StubOutWithMock(flavors, 'extract_flavor')
+        self.mox.StubOutWithMock(self.task,
+                '_check_compatible_with_source_hypervisor')
+        self.mox.StubOutWithMock(self.task, '_call_livem_checks_on_host')
+
+        self.task.image_service.show(self.context,
+                                     self.instance_image).AndReturn("image")
+        flavors.extract_flavor(self.instance).AndReturn("inst_type")
+        self.task._check_compatible_with_source_hypervisor("host1")
+        self.task._call_livem_checks_on_host("host1")\
+                .AndRaise(exception.Invalid)
+
+        self.task._check_compatible_with_source_hypervisor("host1")
+        self.task._call_livem_checks_on_host("host1")
+
+        self.mox.ReplayAll()
+        self.assertEqual("host1", self.task._find_destination())
+
+    def test_find_destination_retry_exceeds_max(self):
+        self.flags(scheduler_max_attempts=1)
+        self.mox.StubOutWithMock(self.task.image_service, 'show')
+        self.mox.StubOutWithMock(flavors, 'extract_flavor')
+        self.mox.StubOutWithMock(self.task,
+                '_check_compatible_with_source_hypervisor')
+        self.mox.StubOutWithMock(self.task, '_call_livem_checks_on_host')
+
+        self.task.image_service.show(self.context,
+                                     self.instance_image).AndReturn("image")
+        flavors.extract_flavor(self.instance).AndReturn("inst_type")
+        self.task._check_compatible_with_source_hypervisor("host1")\
+                .AndRaise(exception.DestinationHypervisorTooOld)
+
+        self.mox.ReplayAll()
+        self.assertRaises(exception.NoValidHost, self.task._find_destination)
+
+    def test_not_implemented_rollback(self):
+        self.assertRaises(NotImplementedError, self.task.rollback)