Add config for cinder mounting needs

This patch adds a config option 'mount_point_base' by which we can
provide the mount point for *fs volumes.
The different types of FS drivers will have separate directory for
mounting their volumes,
Eg: <mount_point_base>/nfs, <mount_point_base>/xyzfs etc.
The default mount point for *fs volumes is /var/lib/glance/mnt/*fs.

Closes-Bug: #1866966

Change-Id: I10b5ea4943ad9388ce1962eae9204b905c8ff24a

glance_store/_drivers/cinder.py

@@ -332,6 +332,15 @@ Possible values:
 Related options:
     * cinder_enforce_multipath
 
+"""),
+    cfg.StrOpt('cinder_mount_point_base',
+               default='/var/lib/glance/mnt',
+               help="""
+Directory where the NFS volume is mounted on the glance node.
+
+Possible values:
+
+* A string representing absolute path of mount point.
 """),
 ]
 
@@ -531,9 +540,12 @@ class Store(glance_store.driver.Store):
                 self.conf, self.backend_group).cinder_use_multipath
             enforce_multipath = getattr(
                 self.conf, self.backend_group).cinder_enforce_multipath
+            mount_point_base = getattr(
+                self.conf, self.backend_group).cinder_mount_point_base
         else:
             use_multipath = self.conf.glance_store.cinder_use_multipath
             enforce_multipath = self.conf.glance_store.cinder_enforce_multipath
+            mount_point_base = self.conf.glance_store.cinder_mount_point_base
 
         properties = connector.get_connector_properties(
             root_helper, host, use_multipath, enforce_multipath)
@@ -548,6 +560,9 @@ class Store(glance_store.driver.Store):
 
         try:
             connection_info = volume.initialize_connection(volume, properties)
+            if connection_info['driver_volume_type'] == 'nfs':
+                connection_info['mount_point_base'] = os.path.join(
+                    mount_point_base, 'nfs')
             conn = connector.InitiatorConnector.factory(
                 connection_info['driver_volume_type'], root_helper,
                 conn=connection_info)

glance_store/tests/unit/test_cinder_store.py

@@ -148,6 +148,7 @@ class TestCinderStore(base.StoreBaseTest,
     def _test_open_cinder_volume(self, open_mode, attach_mode, error,
                                  multipath_supported=False,
                                  enforce_multipath=False):
+        self.config(cinder_mount_point_base=None)
         fake_volume = mock.MagicMock(id=str(uuid.uuid4()), status='available')
         fake_volumes = FakeObject(get=lambda id: fake_volume,
                                   detach=mock.Mock())

glance_store/tests/unit/test_multistore_cinder.py

@@ -168,6 +168,7 @@ class TestMultiCinderStore(base.MultiStoreBaseTest,
     def _test_open_cinder_volume(self, open_mode, attach_mode, error,
                                  multipath_supported=False,
                                  enforce_multipath=False):
+        self.config(cinder_mount_point_base=None, group='cinder1')
         fake_volume = mock.MagicMock(id=str(uuid.uuid4()), status='available')
         fake_volumes = FakeObject(get=lambda id: fake_volume,
                                   detach=mock.Mock())

glance_store/tests/unit/test_opts.py

@@ -75,6 +75,7 @@ class OptsTestCase(base.StoreBaseTest):
             'cinder_catalog_info',
             'cinder_endpoint_template',
             'cinder_http_retries',
+            'cinder_mount_point_base',
             'cinder_os_region_name',
             'cinder_state_transition_timeout',
             'cinder_store_auth_address',