Merge "ceph backup support for EXCLUSIVE_LOCK and JOURNALING features"

cinder/backup/drivers/ceph.py

@@ -88,6 +88,9 @@ service_opts = [
                help='RBD stripe unit to use when creating a backup image.'),
     cfg.IntOpt('backup_ceph_stripe_count', default=0,
                help='RBD stripe count to use when creating a backup image.'),
+    cfg.BoolOpt('backup_ceph_image_journals', default=False,
+                help='If True, apply JOURNALING and EXCLUSIVE_LOCK feature '
+                     'bits to the backup RBD objects to allow mirroring'),
     cfg.BoolOpt('restore_discard_excess_bytes', default=True,
                 help='If True, always discard excess bytes when restoring '
                      'volumes i.e. pad with zeroes.')
@@ -222,6 +225,16 @@ class CephBackupDriver(driver.BackupDriver):
         """Determine if striping is supported by our version of librbd."""
         return hasattr(self.rbd, 'RBD_FEATURE_STRIPINGV2')
 
+    @property
+    def _supports_exclusive_lock(self):
+        """Determine if exclusive-lock is supported by librbd."""
+        return hasattr(self.rbd, 'RBD_FEATURE_EXCLUSIVE_LOCK')
+
+    @property
+    def _supports_journaling(self):
+        """Determine if journaling is supported by our version of librbd."""
+        return hasattr(self.rbd, 'RBD_FEATURE_JOURNALING')
+
     def _get_rbd_support(self):
         """Determine RBD features supported by our version of librbd."""
         old_format = True
@@ -233,6 +246,25 @@ class CephBackupDriver(driver.BackupDriver):
             old_format = False
             features |= self.rbd.RBD_FEATURE_STRIPINGV2
 
+        # journaling requires exclusive_lock; check both together
+        if CONF.backup_ceph_image_journals:
+            if self._supports_exclusive_lock and self._supports_journaling:
+                old_format = False
+                features |= (self.rbd.RBD_FEATURE_EXCLUSIVE_LOCK |
+                             self.rbd.RBD_FEATURE_JOURNALING)
+            else:
+                # FIXME (tasker): when the backup manager supports loading the
+                #   driver during its initialization, this exception should be
+                #   moved to the driver's initialization so that it can stop
+                #   the service from starting when the underyling RBD does not
+                #   support the requested features.
+                LOG.error(_LE("RBD journaling not supported - unable to "
+                              "support per image mirroring in backup pool"))
+                raise exception.BackupInvalidCephArgs(
+                    _("Image Journaling set but RBD backend does "
+                      "not support journaling")
+                )
+
         return (old_format, features)
 
     def _connect_to_rados(self, pool=None):

cinder/tests/unit/backup/drivers/test_backup_ceph.py

@@ -22,6 +22,7 @@ import uuid
 import mock
 from os_brick.initiator import linuxrbd
 from oslo_concurrency import processutils
+from oslo_config import cfg
 from oslo_serialization import jsonutils
 from oslo_utils import units
 import six
@@ -42,6 +43,8 @@ from cinder.tests.unit import fake_constants as fake
 # NOTE: this must be initialised in test setUp().
 RAISED_EXCEPTIONS = []
 
+CONF = cfg.CONF
+
 
 class MockException(Exception):
 
@@ -202,8 +205,13 @@ class BackupCephTestCase(test.TestCase):
     def test_get_rbd_support(self):
         del self.service.rbd.RBD_FEATURE_LAYERING
         del self.service.rbd.RBD_FEATURE_STRIPINGV2
+        del self.service.rbd.RBD_FEATURE_EXCLUSIVE_LOCK
+        del self.service.rbd.RBD_FEATURE_JOURNALING
         self.assertFalse(hasattr(self.service.rbd, 'RBD_FEATURE_LAYERING'))
         self.assertFalse(hasattr(self.service.rbd, 'RBD_FEATURE_STRIPINGV2'))
+        self.assertFalse(hasattr(self.service.rbd,
+                                 'RBD_FEATURE_EXCLUSIVE_LOCK'))
+        self.assertFalse(hasattr(self.service.rbd, 'RBD_FEATURE_JOURNALING'))
 
         oldformat, features = self.service._get_rbd_support()
         self.assertTrue(oldformat)
@@ -221,6 +229,28 @@ class BackupCephTestCase(test.TestCase):
         self.assertFalse(oldformat)
         self.assertEqual(1 | 2, features)
 
+        # initially, backup_ceph_image_journals = False. test that
+        #   the flags are defined, but that they are not returned.
+        self.service.rbd.RBD_FEATURE_EXCLUSIVE_LOCK = 4
+
+        oldformat, features = self.service._get_rbd_support()
+        self.assertFalse(oldformat)
+        self.assertEqual(1 | 2, features)
+
+        self.service.rbd.RBD_FEATURE_JOURNALING = 64
+
+        oldformat, features = self.service._get_rbd_support()
+        self.assertFalse(oldformat)
+        self.assertEqual(1 | 2, features)
+
+        # test that the config setting properly sets the FEATURE bits.
+        #   because journaling requires exclusive-lock, these are set
+        #   at the same time.
+        CONF.set_override("backup_ceph_image_journals", True)
+        oldformat, features = self.service._get_rbd_support()
+        self.assertFalse(oldformat)
+        self.assertEqual(1 | 2 | 4 | 64, features)
+
     @common_mocks
     def test_get_most_recent_snap(self):
         last = 'backup.%s.snap.9824923.1212' % (uuid.uuid4())

releasenotes/notes/backup-ceph-driver-journaling-exculsive-lock-features-6b6044138a288a83.yaml

@@ -0,0 +1,4 @@
+---
+features:
+  - Added new BoolOpt ``backup_ceph_image_journals`` for enabling the Ceph
+    image features required to support RBD mirroring of Cinder backup pool.