Merge "refresh instances_path when shared storage used" into stable/mitaka

2 files changed, 28 insertions, 0 deletions

diff --git a/nova/tests/unit/virt/libvirt/test_driver.py b/nova/tests/unit/virt/libvirt/test_driver.py
index 059999748f..6276f11ca0 100644
--- a/nova/tests/unit/virt/libvirt/test_driver.py
+++ b/nova/tests/unit/virt/libvirt/test_driver.py
@@ -6428,6 +6428,26 @@ class LibvirtConnTestCase(test.NoDBTestCase):
         drvr.check_can_live_migrate_destination_cleanup(self.context,
                                                         dest_check_data)
 
+    @mock.patch('os.path.exists', return_value=True)
+    @mock.patch('os.utime')
+    def test_check_shared_storage_test_file_exists(self, mock_utime,
+                                                   mock_path_exists):
+        tmpfile_path = os.path.join(CONF.instances_path, 'tmp123')
+        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
+        self.assertTrue(drvr._check_shared_storage_test_file('tmp123'))
+        mock_utime.assert_called_once_with(CONF.instances_path, None)
+        mock_path_exists.assert_called_once_with(tmpfile_path)
+
+    @mock.patch('os.path.exists', return_value=False)
+    @mock.patch('os.utime')
+    def test_check_shared_storage_test_file_does_not_exist(self, mock_utime,
+                                                   mock_path_exists):
+        tmpfile_path = os.path.join(CONF.instances_path, 'tmp123')
+        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
+        self.assertFalse(drvr._check_shared_storage_test_file('tmp123'))
+        mock_utime.assert_called_once_with(CONF.instances_path, None)
+        mock_path_exists.assert_called_once_with(tmpfile_path)
+
     def _mock_can_live_migrate_source(self, block_migration=False,
                                       is_shared_block_storage=False,
                                       is_shared_instance_path=False,
diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index 8c1e27a8c7..78f9c7ca01 100644
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -5749,6 +5749,14 @@ class LibvirtDriver(driver.ComputeDriver):
 
         Cannot confirm tmpfile return False.
         """
+        # NOTE(tpatzig): if instances_path is a shared volume that is
+        # under heavy IO (many instances on many compute nodes),
+        # then checking the existence of the testfile fails,
+        # just because it takes longer until the client refreshes and new
+        # content gets visible.
+        # os.utime (like touch) on the directory forces the client to refresh.
+        os.utime(CONF.instances_path, None)
+
         tmp_file = os.path.join(CONF.instances_path, filename)
         if not os.path.exists(tmp_file):
             return False