Add limited retype support for rbd

This patch enables limited retype support for rbd. In addition to
basic retyping between volume types that only differ in their name,
retyping between volume types that imply a change of the qos_specs
are supported. This hence allows to adapt the quality-of-service
settings of a volume after its creation.

All other changes, such as host migration, change of encryption or
changes of settings as defined by the extra_specs are not supported
by this commit and left for later patches.

Implements: blueprint ceph-rbd-support-retype
Change-Id: Ib9edf83eb3ade1e6b2dcf1121a16a6f2e68753e1

diff --git a/cinder/tests/test_rbd.py b/cinder/tests/test_rbd.py
index 8c721b24f756343ebca5873a5e653053a56b2e74..f40409b464f9cff20ad1891e8ca9c5446e63eadb 100644 (file)
--- a/cinder/tests/test_rbd.py
+++ b/cinder/tests/test_rbd.py
@@ -736,6 +736,36 @@ class RBDTestCase(test.TestCase):
 
         self.mox.VerifyAll()
 
+    @common_mocks
+    def test_retype(self):
+        context = {}
+        diff = {'encryption': {},
+                'extra_specs': {}}
+        fake_volume = {'name': 'testvolume',
+                       'host': 'currenthost'}
+        fake_type = 'high-IOPS'
+
+        # no support for migration
+        host = {'host': 'anotherhost'}
+        self.assertFalse(self.driver.retype(context, fake_volume,
+                                            fake_type, diff, host))
+        host = {'host': 'currenthost'}
+
+        # no support for changing encryption
+        diff['encryption'] = {'non-empty': 'non-empty'}
+        self.assertFalse(self.driver.retype(context, fake_volume,
+                                            fake_type, diff, host))
+        diff['encryption'] = {}
+
+        # no support for changing extra_specs
+        diff['extra_specs'] = {'non-empty': 'non-empty'}
+        self.assertFalse(self.driver.retype(context, fake_volume,
+                                            fake_type, diff, host))
+        diff['extra_specs'] = {}
+
+        self.assertTrue(self.driver.retype(context, fake_volume,
+                                           fake_type, diff, host))
+
     def test_rbd_volume_proxy_init(self):
         mock_driver = mock.Mock(name='driver')
         mock_driver._connect_to_rados.return_value = (None, None)

diff --git a/cinder/volume/drivers/rbd.py b/cinder/volume/drivers/rbd.py
index 2ccbb0e3525b605673dc98b3104f84ad248ea724..3c7dda251132b8e528a7b7c96a6f70cd50f8f149 100644 (file)
--- a/cinder/volume/drivers/rbd.py
+++ b/cinder/volume/drivers/rbd.py
@@ -696,6 +696,31 @@ class RBDDriver(driver.VolumeDriver):
                     raise exception.SnapshotIsBusy(snapshot_name=snap_name)
             volume.remove_snap(snap_name)
 
+    def retype(self, context, volume, new_type, diff, host):
+        """Retypes a volume, allows QoS change only."""
+        LOG.debug('Retype volume request %(vol)s to be %(type)s '
+                  '(host: %(host)s), diff %(diff)s.',
+                  {
+                      'vol': volume['name'],
+                      'type': new_type,
+                      'host': host,
+                      'diff': diff
+                  })
+
+        if volume['host'] != host['host']:
+            LOG.error(_LE('Retype with host migration not supported'))
+            return False
+
+        if diff['encryption']:
+            LOG.error(_LE('Retype of encryption type not supported'))
+            return False
+
+        if diff['extra_specs']:
+            LOG.error(_LE('Retype of extra_specs not supported'))
+            return False
+
+        return True
+
     def ensure_export(self, context, volume):
         """Synchronously recreates an export for a logical volume."""
         pass