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Libvirt: disallow live-mig for volume-backed with local disk
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This patch makes libvirt raise an error if a live migration was
requested without shared storage for a volume-backed instance, if that
instance has any local disks.

The reason is that without shared storage, local disks will be
re-created on the destination node which can result in loss of data.

Change-Id: Ic96dabf6020e957309280862b325792faf44b1f5
Closes-bug: 1236356
(cherry picked from commit cf89e78)
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@djipko @russellb
djipko authored and russellb committed Oct 11, 2013
1 parent 49d60d1 commit c63f4af
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Showing 2 changed files with 34 additions and 1 deletion.
31 changes: 31 additions & 0 deletions nova/tests/virt/libvirt/test_libvirt.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2861,6 +2861,8 @@ def test_check_can_live_migrate_source_works_correctly(self):

self.mox.StubOutWithMock(conn, "_check_shared_storage_test_file")
conn._check_shared_storage_test_file("file").AndReturn(False)
self.mox.StubOutWithMock(conn, "get_instance_disk_info")
conn.get_instance_disk_info(instance_ref['name']).AndReturn('[]')

self.mox.StubOutWithMock(conn, "_assert_dest_node_has_enough_disk")
conn._assert_dest_node_has_enough_disk(
Expand All @@ -2881,12 +2883,32 @@ def test_check_can_live_migrate_source_vol_backed_works_correctly(self):
conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
self.mox.StubOutWithMock(conn, "_check_shared_storage_test_file")
conn._check_shared_storage_test_file("file").AndReturn(False)
self.mox.StubOutWithMock(conn, "get_instance_disk_info")
conn.get_instance_disk_info(instance_ref['name']).AndReturn('[]')
self.mox.ReplayAll()
ret = conn.check_can_live_migrate_source(self.context, instance_ref,
dest_check_data)
self.assertTrue(type(ret) == dict)
self.assertTrue('is_shared_storage' in ret)

def test_check_can_live_migrate_source_vol_backed_w_disk_raises(self):
instance_ref = db.instance_create(self.context, self.test_instance)
dest_check_data = {"filename": "file",
"block_migration": False,
"disk_over_commit": False,
"disk_available_mb": 1024,
"is_volume_backed": True}
conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
self.mox.StubOutWithMock(conn, "_check_shared_storage_test_file")
conn._check_shared_storage_test_file("file").AndReturn(False)
self.mox.StubOutWithMock(conn, "get_instance_disk_info")
conn.get_instance_disk_info(instance_ref['name']).AndReturn(
'[{"fake_disk_attr": "fake_disk_val"}]')
self.mox.ReplayAll()
self.assertRaises(exception.InvalidSharedStorage,
conn.check_can_live_migrate_source, self.context,
instance_ref, dest_check_data)

def test_check_can_live_migrate_source_vol_backed_fails(self):
instance_ref = db.instance_create(self.context, self.test_instance)
dest_check_data = {"filename": "file",
Expand All @@ -2897,6 +2919,9 @@ def test_check_can_live_migrate_source_vol_backed_fails(self):
conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
self.mox.StubOutWithMock(conn, "_check_shared_storage_test_file")
conn._check_shared_storage_test_file("file").AndReturn(False)
self.mox.StubOutWithMock(conn, "get_instance_disk_info")
conn.get_instance_disk_info(instance_ref['name']).AndReturn(
'[{"fake_disk_attr": "fake_disk_val"}]')
self.mox.ReplayAll()
self.assertRaises(exception.InvalidSharedStorage,
conn.check_can_live_migrate_source, self.context,
Expand All @@ -2912,6 +2937,8 @@ def test_check_can_live_migrate_dest_fail_shared_storage_with_blockm(self):

self.mox.StubOutWithMock(conn, "_check_shared_storage_test_file")
conn._check_shared_storage_test_file("file").AndReturn(True)
self.mox.StubOutWithMock(conn, "get_instance_disk_info")
conn.get_instance_disk_info(instance_ref['name']).AndReturn('[]')

self.mox.ReplayAll()
self.assertRaises(exception.InvalidLocalStorage,
Expand All @@ -2928,6 +2955,8 @@ def test_check_can_live_migrate_no_shared_storage_no_blck_mig_raises(self):

self.mox.StubOutWithMock(conn, "_check_shared_storage_test_file")
conn._check_shared_storage_test_file("file").AndReturn(False)
self.mox.StubOutWithMock(conn, "get_instance_disk_info")
conn.get_instance_disk_info(instance_ref['name']).AndReturn('[]')

self.mox.ReplayAll()
self.assertRaises(exception.InvalidSharedStorage,
Expand All @@ -2944,6 +2973,8 @@ def test_check_can_live_migrate_source_with_dest_not_enough_disk(self):
self.mox.StubOutWithMock(conn, "get_instance_disk_info")
conn.get_instance_disk_info(instance_ref["name"]).AndReturn(
'[{"virt_disk_size":2}]')
conn.get_instance_disk_info(instance_ref["name"]).AndReturn(
'[{"virt_disk_size":2}]')

dest_check_data = {"filename": "file",
"disk_available_mb": 0,
Expand Down
4 changes: 3 additions & 1 deletion nova/virt/libvirt/driver.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3812,6 +3812,8 @@ def check_can_live_migrate_source(self, context, instance,
filename = dest_check_data["filename"]
block_migration = dest_check_data["block_migration"]
is_volume_backed = dest_check_data.get('is_volume_backed', False)
has_local_disks = bool(
jsonutils.loads(self.get_instance_disk_info(instance['name'])))

shared = self._check_shared_storage_test_file(filename)

Expand All @@ -3824,7 +3826,7 @@ def check_can_live_migrate_source(self, context, instance,
dest_check_data['disk_available_mb'],
dest_check_data['disk_over_commit'])

elif not shared and not is_volume_backed:
elif not shared and (not is_volume_backed or has_local_disks):
reason = _("Live migration can not be used "
"without shared storage.")
raise exception.InvalidSharedStorage(reason=reason, path=source)
Expand Down

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