Auto assign volume device name during attachment

In current powervc driver code, our sync code will always set the nova
instance root_device_name as None, this will break nova framework's
device name auto-assign function if the device name is not provide while
volume attachment. PowerVC itself will not set it's instance
root_device_name from it's implemenation, for PowerVC driver, we just
get the device name of the boot volume from the powervc side, and make
it as the root_device_name of the nova instance.

Closes-Bug: #1369577
Change-Id: I7e71573e7b83ec9f8c34cfa4f0a1736b90402a90

nova-powervc/powervc/nova/driver/compute/manager.py

@@ -359,7 +359,10 @@ class PowerVCCloudManager(manager.Manager):
         else:
             ephemeral_gb = flavor.get('ephemeral_gb')
 
-        root_device_name = None  # Don't know what is this for.
+        # need to set the root_device_name for the volume attachment auto
+        # assigned device name purpose
+        root_device_name = self._get_instance_root_device_name(pvc_instance,
+                                                               db_instance)
 
         address4 = pvc_instance['accessIPv4']
         # Has to be a valid IP, or null
@@ -1921,3 +1924,23 @@ class PowerVCCloudManager(manager.Manager):
                                                                     nets,
                                                                     port_ids)
                     LOG.info("_fix_instance_nw_info" + str(nw_info))
+
+    def _get_instance_root_device_name(self, pvc_instance, db_instance):
+        root_device_name = '/dev/sda'
+        if db_instance and db_instance.get('root_device_name'):
+            LOG.info("root_device_name %s from local db"
+                     % db_instance.get('root_device_name'))
+            return db_instance.get('root_device_name')
+        if not pvc_instance:
+            LOG.info("set root_device_name as default: %s " % root_device_name)
+            return root_device_name
+        pvc_id = pvc_instance.get('id')
+        if not pvc_id:
+            LOG.info("set root_device_name as default: %s " % root_device_name)
+            return root_device_name
+        pvc_root_device_name = self.driver.get_pvc_root_device_name(pvc_id)
+        if pvc_root_device_name:
+            root_device_name = pvc_root_device_name
+            LOG.info("set root_device_name as powervc boot volume device "
+                     "name: %s " % root_device_name)
+        return root_device_name

nova-powervc/powervc/nova/driver/virt/powervc/driver.py

@@ -39,6 +39,7 @@ class PowerVCDriver(driver.ComputeDriver):
     password for the target IBM PowerVC system.
     """
     nc = None
+    cached_root_device_map = {}
 
     def __init__(self, virtapi):
         self.virtapi = virtapi
@@ -1431,3 +1432,18 @@ class PowerVCDriver(driver.ComputeDriver):
 
         localvolume = localvolumes[0]
         return localvolume.id
+
+    def get_pvc_root_device_name(self, pvc_id):
+        if not self.cached_root_device_map.get(pvc_id):
+            return self.cached_root_device_map.get(pvc_id)
+        list_all_volumes = self._service._pvccinderclient.\
+            volumes.list_all_volumes
+        volume_search_opts = {'metadata': {'is_boot_volume': 'True'}}
+        pvcvolumes = list_all_volumes(search_opts=volume_search_opts)
+        for pvcvolume in pvcvolumes:
+            pvcvolume_attachments = pvcvolume.attachments
+            if len(pvcvolume_attachments) == 0:
+                continue
+            device_name = pvcvolume_attachments[0].get('device')
+            self.cached_root_device_map[pvc_id] = device_name
+        return self.cached_root_device_map.get(pvc_id)

nova-powervc/powervc/nova/driver/virt/powervc/service.py

@@ -54,6 +54,8 @@ class PowerVCService(object):
         from powervc.common.client import factory
         self._cinderclient = factory.\
             LOCAL.new_client(str(common_constants.SERVICE_TYPES.volume))
+        self._pvccinderclient = factory.\
+            POWERVC.new_client(str(common_constants.SERVICE_TYPES.volume))
         self.max_tries = CONF.powervc.volume_max_try_times
 
         self.longrun_loop_interval = CONF.powervc.longrun_loop_interval

nova-powervc/test/compute/test_sync_instance.py

@@ -97,6 +97,12 @@ class TestSyncInstance(unittest.TestCase):
         flavors.save_flavor_info(dict(), self.osflavor.os_flavor)\
             .AndReturn("system_metadata")
 
+        self.moxer.StubOutWithMock(self.PowerVCCloudManager,
+                                   "_get_instance_root_device_name")
+
+        getInsRDN = self.PowerVCCloudManager._get_instance_root_device_name
+        getInsRDN(pvc_instance, None).AndReturn("/dev/sda")
+
         self.moxer.ReplayAll()
 
         ins, image, flavor = self.PowerVCCloudManager.\

nova-powervc/test/fake_os_instance.py

@@ -76,7 +76,7 @@ class FakeOSInstance():
             "72bb2b5af241413172ad4cf38354e727ce317843ee2432c36439643c"
         self.os_instance['hostname'] = "IVT-Test17"
         self.os_instance['access_ip_v4'] = None
-        self.os_instance['root_device_name'] = None
+        self.os_instance['root_device_name'] = "/dev/sda"
         self.os_instance['system_metadata'] = "system_metadata"
         self.os_instance['vm_state'] = "active"
         self.os_instance['task_state'] = None