Changes required for Cold Migration

- "block_device_info" required to delete instance that migrated form
  one host to another
- Skip check for RMC state during migration
- Skipping check for reducing disk size in case of cold migration.

Change-Id: I8ad1fc2852e0a281c8a48b207ea4fd2f2beac467

nova_powervm/tests/virt/powervm/test_driver.py

@@ -1378,13 +1378,17 @@ class TestPowerVMDriver(test.NoDBTestCase):
         # BDMs
         mock_bdms = self._fake_bdms()
 
-        # Catch root disk resize smaller.
-        small_root = objects.Flavor(vcpus=1, memory_mb=2048, root_gb=9)
-        self.assertRaises(
-            exc.InstanceFaultRollback, self.drv.migrate_disk_and_power_off,
-            'context', self.inst, 'dest', small_root, 'network_info',
-            mock_bdms)
+        # IBM cherry-pick start
+        dest_host = host + '1'
+        # Catch root disk resize smaller
+        if dest_host == host:
+            small_root = objects.Flavor(vcpus=1, memory_mb=2048, root_gb=9)
+            self.assertRaises(
+                exc.InstanceFaultRollback, self.drv.migrate_disk_and_power_off,
+                'context', self.inst, 'dest', small_root, 'network_info',
+                mock_bdms)
 
+        # IBM cherry-pick end
         # Boot disk resize
         boot_flav = objects.Flavor(vcpus=1, memory_mb=2048, root_gb=12)
         # Tasks expected to be added for migrate
@@ -1397,7 +1401,6 @@ class TestPowerVMDriver(test.NoDBTestCase):
             'fake',
             'rename_vm_migrate_instance-00000001',
         ]
-        dest_host = host + '1'
         with fx.DriverTaskFlow() as taskflow_fix:
             self.drv.migrate_disk_and_power_off(
                 'context', self.inst, dest_host, boot_flav, 'network_info',
@@ -2068,13 +2071,19 @@ class TestPowerVMDriver(test.NoDBTestCase):
         mock_power_off.assert_called_once_with(
             self.drv.adapter, self.inst, force_immediate=False, timeout=500)
 
+    @mock.patch('nova_powervm.virt.powervm.driver.'
+                'PowerVMDriver._get_block_device_info')
     @mock.patch('nova_powervm.virt.powervm.driver.PowerVMDriver._destroy')
-    def test_confirm_migration_diff_host(self, mock_destroy):
+    def test_confirm_migration_diff_host(self, mock_destroy,
+                                         mock_block_device_info):
         mock_mig = mock.Mock(source_compute='host1', dest_compute='host2')
         self.drv.confirm_migration('context', mock_mig, self.lpm_inst,
                                    'network_info')
+        mock_block_device_info.assert_called_once_with('context',
+                                                       self.lpm_inst)
         mock_destroy.assert_called_once_with(
-            'context', self.lpm_inst, block_device_info=None,
+            'context', self.lpm_inst,
+            block_device_info=mock_block_device_info.return_value,
             destroy_disks=False, shutdown=False)
 
     @mock.patch('nova_powervm.virt.powervm.vm.rename', autospec=True)

nova_powervm/tests/virt/powervm/test_live_migration.py

@@ -129,6 +129,65 @@ class TestLPM(test.NoDBTestCase):
             mock_vterm_close.assert_called_once_with(
                 self.apt, mock_wrap.uuid)
 
+    @mock.patch('pypowervm.tasks.storage.ScrubOrphanStorageForLpar',
+                autospec=True)
+    @mock.patch('nova_powervm.virt.powervm.media.ConfigDrivePowerVM',
+                autospec=True)
+    @mock.patch('nova_powervm.virt.powervm.vm.get_instance_wrapper',
+                autospec=True)
+    @mock.patch('pypowervm.tasks.vterm.close_vterm', autospec=True)
+    def test_lpm_source_for_cold_migration(self, mock_vterm_close,
+                                           mock_get_wrap,
+                                           mock_cd, mock_scrub):
+        self.host_mig_data['active_migrations_supported'] = 4
+        self.host_mig_data['active_migrations_in_progress'] = 2
+
+        # Test the bad path first, then patch in values to make succeed
+        mock_wrap = mock.Mock(id=123)
+        mock_get_wrap.return_value = mock_wrap
+
+        self.assertRaises(exception.MigrationPreCheckError,
+                          self.lpmsrc.check_source, 'context',
+                          'block_device_info', [])
+
+        # Patch the proc compat fields, to get further
+        pm = mock.PropertyMock(return_value='b')
+        type(mock_wrap).proc_compat_mode = pm
+
+        self.assertRaises(exception.MigrationPreCheckError,
+                          self.lpmsrc.check_source, 'context',
+                          'block_device_info', [])
+
+        pm = mock.PropertyMock(return_value='Not_Migrating')
+        type(mock_wrap).migration_state = pm
+
+        # Get a volume driver.
+        mock_vol_drv = mock.MagicMock()
+
+        # Finally, good path.
+        self.lpmsrc.check_source('context', 'block_device_info',
+                                 [mock_vol_drv])
+        # Ensure we built a scrubber.
+        mock_scrub.assert_called_with(mock.ANY, 123)
+        # Ensure we added the subtasks to remove the vopts.
+        mock_cd.return_value.dlt_vopt.assert_called_once_with(
+            mock.ANY, stg_ftsk=mock_scrub.return_value,
+            remove_mappings=False)
+        # And ensure the scrubber was executed
+        mock_scrub.return_value.execute.assert_called_once_with()
+        mock_vol_drv.pre_live_migration_on_source.assert_called_once_with(
+            {})
+
+        # Ensure migration counts are validated
+        self.host_mig_data['active_migrations_in_progress'] = 4
+        self.assertRaises(exception.MigrationPreCheckError,
+                          self.lpmsrc.check_source, 'context',
+                          'block_device_info', [])
+
+        # Ensure the vterm was closed
+        mock_vterm_close.assert_called_once_with(
+            self.apt, mock_wrap.uuid)
+
     def test_lpm_dest(self):
         src_compute_info = {'stats': {'memory_region_size': 1}}
         dst_compute_info = {'stats': {'memory_region_size': 1}}

nova_powervm/virt/powervm/driver.py

@@ -1190,12 +1190,14 @@ class PowerVMDriver(driver.ComputeDriver):
 
         disk_info = {}
 
-        if flavor and flavor.root_gb < instance.root_gb:
-            raise exception.InstanceFaultRollback(
-                exception.ResizeError(reason=_('Cannot reduce disk size.')))
-
         same_host = dest == self.get_host_ip_addr()
         if same_host:
+            # IBM cherry-pick start
+            if flavor and flavor.root_gb < instance.root_gb:
+                raise exception.InstanceFaultRollback(
+                    exception.ResizeError(
+                        reason=_('Cannot reduce disk size.')))
+            # IBM cherry-pick end
             self._log_operation('resize', instance)
         else:
             self._log_operation('migration', instance)
@@ -1412,7 +1414,8 @@ class PowerVMDriver(driver.ComputeDriver):
 
         # Destroy the old VM.
         destroy_disks = not self.disk_dvr.capabilities['shared_storage']
-        self._destroy(context, instance, block_device_info=None,
+        block_device_info = self._get_block_device_info(context, instance)
+        self._destroy(context, instance, block_device_info=block_device_info,
                       destroy_disks=destroy_disks, shutdown=False)
 
     def finish_revert_migration(self, context, instance, network_info,

nova_powervm/virt/powervm/live_migration.py

@@ -18,6 +18,7 @@
 import abc
 import six
 
+from nova.compute import power_state
 from nova import exception
 from nova.objects import migrate_data as mig_obj
 from oslo_log import log as logging
@@ -291,7 +292,9 @@ class LiveMigrationSrc(LiveMigration):
             raise exception.MigrationPreCheckError(reason=msg)
 
         # Check if VM is ready for migration
-        self._check_migration_ready(lpar_w, self.drvr.host_wrapper)
+        # Skip incase of cold migration
+        if self.instance.power_state == power_state.RUNNING:
+            self._check_migration_ready(lpar_w, self.drvr.host_wrapper)
 
         if lpar_w.migration_state != 'Not_Migrating':
             msg = (_("Live migration of instance '%(name)s' failed because "