Allows libvirt to set a serial number for a volume

The serial number defaults to the volume_id of the volume being
attached. We may expose a method in the future to set a different
serial number when creating or attaching a volume.

The purpose of this change is to give users a consistent place
they can find their volume. It should show up now in most flavors
of linux under /disk/by-id/virtio-<volume_uuid>

Fixes bug 1004328

Change-Id: Id1c56b5b23d799deb7da2d39ae57ecb48965c55f

3 files changed, 33 insertions, 1 deletions

diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index 75e6f1f8a..c9c52d560 100644
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -811,6 +811,8 @@ class ComputeManager(manager.SchedulerDependentManager):
         for bdm in bdms:
             try:
                 cinfo = jsonutils.loads(bdm['connection_info'])
+                if cinfo and 'serial' not in cinfo:
+                    cinfo['serial'] = bdm['volume_id']
                 bdmap = {'connection_info': cinfo,
                          'mount_device': bdm['device_name'],
                          'delete_on_termination': bdm['delete_on_termination']}
@@ -2076,6 +2078,10 @@ class ComputeManager(manager.SchedulerDependentManager):
                 LOG.exception(msg % locals(), context=context,
                               instance=instance)
                 self.volume_api.unreserve_volume(context, volume)
+
+        if 'serial' not in connection_info:
+            connection_info['serial'] = volume_id
+
         try:
             self.driver.attach_volume(connection_info,
                                       instance['name'],
@@ -2117,7 +2123,12 @@ class ComputeManager(manager.SchedulerDependentManager):
         if instance['name'] not in self.driver.list_instances():
             LOG.warn(_('Detaching volume from unknown instance'),
                      context=context, instance=instance)
-        self.driver.detach_volume(jsonutils.loads(bdm['connection_info']),
+        connection_info = jsonutils.loads(bdm['connection_info'])
+        # NOTE(vish): We currently don't use the serial when disconnecting,
+        #             but added for completeness in case we ever do.
+        if connection_info and 'serial' not in connection_info:
+            connection_info['serial'] = volume_id
+        self.driver.detach_volume(connection_info,
                                   instance['name'],
                                   mp)
 
diff --git a/nova/tests/test_libvirt.py b/nova/tests/test_libvirt.py
index 469b48b01..83f83f9d6 100644
--- a/nova/tests/test_libvirt.py
+++ b/nova/tests/test_libvirt.py
@@ -154,6 +154,24 @@ class LibvirtVolumeTestCase(test.TestCase):
             'host': 'fake_host'
         }
 
+    def test_libvirt_volume_driver_serial(self):
+        vol_driver = volume_driver.VolumeDriver()
+        libvirt_driver = volume.LibvirtVolumeDriver(self.fake_conn)
+        name = 'volume-00000001'
+        vol = {'id': 1, 'name': name}
+        connection_info = {
+            'driver_volume_type': 'fake',
+            'data': {
+                    'device_path': '/foo',
+                },
+            'serial': 'fake_serial',
+        }
+        mount_device = "vde"
+        conf = libvirt_driver.connect_volume(connection_info, mount_device)
+        tree = conf.format_dom()
+        self.assertEqual(tree.get('type'), 'block')
+        self.assertEqual(tree.find('./serial').text, 'fake_serial')
+
     def test_libvirt_iscsi_driver(self):
         # NOTE(vish) exists is to make driver assume connecting worked
         self.stubs.Set(os.path, 'exists', lambda x: True)
diff --git a/nova/virt/libvirt/volume.py b/nova/virt/libvirt/volume.py
index 3c286a901..54e6bfbf6 100644
--- a/nova/virt/libvirt/volume.py
+++ b/nova/virt/libvirt/volume.py
@@ -47,6 +47,7 @@ class LibvirtVolumeDriver(object):
         conf.source_path = connection_info['data']['device_path']
         conf.target_dev = mount_device
         conf.target_bus = "virtio"
+        conf.serial = connection_info.get('serial')
         return conf
 
     def disconnect_volume(self, connection_info, mount_device):
@@ -67,6 +68,7 @@ class LibvirtFakeVolumeDriver(LibvirtVolumeDriver):
         conf.source_host = "fake"
         conf.target_dev = mount_device
         conf.target_bus = "virtio"
+        conf.serial = connection_info.get('serial')
         return conf
 
 
@@ -83,6 +85,7 @@ class LibvirtNetVolumeDriver(LibvirtVolumeDriver):
         conf.source_host = connection_info['data']['name']
         conf.target_dev = mount_device
         conf.target_bus = "virtio"
+        conf.serial = connection_info.get('serial')
         netdisk_properties = connection_info['data']
         if netdisk_properties.get('auth_enabled'):
             conf.auth_username = netdisk_properties['auth_username']