RBD Thin Provisioning stats

Allow the RBD driver to work with max_over_subscription_ratio.

This should be expanded to use rbd diff_iterate2() when
Infernalis and newer deployments are widespread.

Co-Authored-By: Ivan Kolodyazhny <e0ne@e0ne.info>
Change-Id: Ida7654545ae46d106908b991c91bab989b998484

cinder/tests/unit/volume/drivers/test_rbd.py

@@ -79,12 +79,13 @@ def common_mocks(f):
 
     def _common_inner_inner1(inst, *args, **kwargs):
         @mock.patch('retrying.Retrying', _FakeRetrying)
+        @mock.patch.object(driver.RBDDriver, '_get_usage_info')
         @mock.patch('cinder.volume.drivers.rbd.RBDVolumeProxy')
         @mock.patch('cinder.volume.drivers.rbd.RADOSClient')
         @mock.patch('cinder.backup.drivers.ceph.rbd')
         @mock.patch('cinder.backup.drivers.ceph.rados')
         def _common_inner_inner2(mock_rados, mock_rbd, mock_client,
-                                 mock_proxy):
+                                 mock_proxy, mock_usage_info):
             inst.mock_rbd = mock_rbd
             inst.mock_rados = mock_rados
             inst.mock_client = mock_client
@@ -821,7 +822,10 @@ class RBDTestCase(test.TestCase):
             storage_protocol='ceph',
             total_capacity_gb=28.44,
             free_capacity_gb=27.0,
-            reserved_percentage=0,
+            reserved_percentage='RBD',
+            thin_provisioning_support=True,
+            provisioned_capacity_gb=0.0,
+            max_over_subscription_ratio='RBD',
             multiattach=False)
 
         actual = self.driver.get_volume_stats(True)
@@ -847,8 +851,11 @@ class RBDTestCase(test.TestCase):
                         storage_protocol='ceph',
                         total_capacity_gb='unknown',
                         free_capacity_gb='unknown',
-                        reserved_percentage=0,
+                        reserved_percentage='RBD',
-                        multiattach=False)
+                        multiattach=False,
+                        provisioned_capacity_gb=0.0,
+                        max_over_subscription_ratio='RBD',
+                        thin_provisioning_support=True)
 
         actual = self.driver.get_volume_stats(True)
         client.cluster.mon_command.assert_called_once_with(

cinder/volume/drivers/rbd.py

@@ -389,6 +389,20 @@ class RBDDriver(driver.TransferVD, driver.ExtendVD,
             ports.append(port)
         return hosts, ports
 
+    def _iterate_cb(self, offset, length, exists):
+        if exists:
+            self._total_usage += length
+
+    def _get_usage_info(self):
+        with RADOSClient(self) as client:
+            for t in self.RBDProxy().list(client.ioctx):
+                if t.startswith('volume'):
+                    # Only check for "volume" to allow some flexibility with
+                    # non-default volume_name_template settings.  Template
+                    # must start with "volume".
+                    with RBDVolumeProxy(self, t, read_only=True) as v:
+                        v.diff_iterate(0, v.size(), None, self._iterate_cb)
+
     def _update_volume_stats(self):
         stats = {
             'vendor_name': 'Open Source',
@@ -396,8 +410,14 @@ class RBDDriver(driver.TransferVD, driver.ExtendVD,
             'storage_protocol': 'ceph',
             'total_capacity_gb': 'unknown',
             'free_capacity_gb': 'unknown',
-            'reserved_percentage': 0,
+            'provisioned_capacity_gb': 0,
+            'reserved_percentage': (
+                self.configuration.safe_get('reserved_percentage')),
             'multiattach': False,
+            'thin_provisioning_support': True,
+            'max_over_subscription_ratio': (
+                self.configuration.safe_get('max_over_subscription_ratio'))
+
         }
         backend_name = self.configuration.safe_get('volume_backend_name')
         stats['volume_backend_name'] = backend_name or 'RBD'
@@ -419,6 +439,11 @@ class RBDDriver(driver.TransferVD, driver.ExtendVD,
                         pool_stats['bytes_used']) / units.Gi
                     stats['total_capacity_gb'] = round(
                         (stats['free_capacity_gb'] + used_capacity_gb), 2)
+
+            self._total_usage = 0
+            self._get_usage_info()
+            total_usage_gb = math.ceil(float(self._total_usage) / units.Gi)
+            stats['provisioned_capacity_gb'] = total_usage_gb
         except self.rados.Error:
             # just log and return unknown capacities
             LOG.exception(_LE('error refreshing volume stats'))

releasenotes/notes/rbd-thin-provisioning-c98522d6fe7b71ff.yaml

@@ -0,0 +1,3 @@
+---
+features:
+  - Allow the RBD driver to work with max_over_subscription_ratio.