Retrieve PartitionInstance via getter method

In some methods we directly created an instance of the PartitionInstnace object.
The instantiation of this object is now moved into a separate method. This is
even more usefull when we introduce ssc support in the future. In that case
we could simply introduce a SSCPartitionInstance class. The newly created method
would be the only place where the decission between ssc and pure dpm is done.

Change-Id: I06e6d8ee84b7f308f2cdbf120c08e46afd4dd8be

nova_dpm/tests/unit/virt/dpm/test_driver.py

@@ -238,7 +238,9 @@ class DPMdriverInitHostTestCase(TestCase):
 
     @mock.patch.object(vm.PartitionInstance, 'get_partition')
     def test_get_volume_connector(self, mock_get_partition):
-        self.dpmdriver.get_volume_connector(mock.Mock())
+        instance = mock.Mock()
+        instance.image_ref = ""
+        self.dpmdriver.get_volume_connector(instance)
 
     def test_get_available_nodes(self):
         self.flags(host="fake-mini")
@@ -312,9 +314,11 @@ class DPMDriverInstanceTestCase(TestCase):
     def test_spawn_max_nics(self, mock_prop, mock_create, mock_get_part):
         dpmdriver = driver.DPMDriver(None)
         network_info = [x for x in range(0, 13)]
+        mock_instance = mock.Mock()
+        mock_instance.image_ref = ""
         self.assertRaises(exceptions.MaxAmountOfInstancePortsExceededError,
-                          dpmdriver.spawn, None, None, None, None, None,
-                          None, network_info)
+                          dpmdriver.spawn, None, mock_instance, None, None,
+                          None, None, network_info)
 
     @mock.patch.object(driver.DPMDriver, 'get_fc_boot_props',
                        return_value=(None, None))
@@ -332,6 +336,7 @@ class DPMDriverInstanceTestCase(TestCase):
 
         mock_instance = mock.Mock()
         mock_instance.uuid = "1"
+        mock_instance.image_ref = ""
 
         vif = {"address": "aa:bb:cc:dd:ee:ff",
                "id": "foo-id",

nova_dpm/virt/dpm/driver.py

@@ -69,6 +69,12 @@ class DPMDriver(driver.ComputeDriver):
 
         self.volume_drivers = self._get_volume_drivers()
 
+    def _get_partition_instance(self, instance):
+        if instance.image_ref != '':
+            raise exceptions.BootFromImageNotSupported()
+        else:
+            return vm.PartitionInstance(instance, self._cpc)
+
     def init_host(self, host):
         """Driver initialization of the hypervisor node"""
         LOG.debug("init_host")
@@ -201,7 +207,7 @@ class DPMDriver(driver.ComputeDriver):
             props['wwpns'] = self.deleted_instance_wwpns_mapping.pop(
                 instance.uuid)
         else:
-            inst = vm.PartitionInstance(instance, self._cpc)
+            inst = self._get_partition_instance(instance)
             props['wwpns'] = inst.get_partition_wwpns()
 
         props['host'] = instance.uuid
@@ -316,7 +322,7 @@ class DPMDriver(driver.ComputeDriver):
         if instance.image_ref != '':
             raise exceptions.BootFromImageNotSupported()
 
-        inst = vm.PartitionInstance(instance, self._cpc)
+        inst = self._get_partition_instance(instance)
         inst.create(inst.properties())
 
         inst.attach_hbas()
@@ -325,7 +331,7 @@ class DPMDriver(driver.ComputeDriver):
               admin_password, allocations, network_info=None,
               block_device_info=None):
 
-        inst = vm.PartitionInstance(instance, self._cpc)
+        inst = self._get_partition_instance(instance)
 
         # The creation of NICs is limited in DPM by the partitions
         # boot-os-specific-parameters property. It is used to pass additional
@@ -422,7 +428,7 @@ class DPMDriver(driver.ComputeDriver):
 
     def destroy(self, context, instance, network_info, block_device_info=None,
                 destroy_disks=True, migrate_data=None):
-        inst = vm.PartitionInstance(instance, self._cpc)
+        inst = self._get_partition_instance(instance)
         # Need to save wwpns before deletion of the partition
         # Because after driver.destroy function driver.get_volume_connector
         # will be called which required hbas wwpns of partition.
@@ -431,15 +437,15 @@ class DPMDriver(driver.ComputeDriver):
         inst.destroy()
 
     def power_off(self, instance, timeout=0, retry_interval=0):
-        inst = vm.PartitionInstance(instance, self._cpc)
+        inst = self._get_partition_instance(instance)
         inst.power_off_vm()
 
     def power_on(self, context, instance, network_info,
                  block_device_info=None):
-        inst = vm.PartitionInstance(instance, self._cpc)
+        inst = self._get_partition_instance(instance)
         inst.power_on_vm()
 
     def reboot(self, context, instance, network_info, reboot_type,
                block_device_info=None, bad_volumes_callback=None):
-        inst = vm.PartitionInstance(instance, self._cpc)
+        inst = self._get_partition_instance(instance)
         inst.reboot_vm()