Check ceph backend connection on driver setup

Check that ceph connection really works when setting up
the driver instead of doing real connect later in init_host
phase. This mitigates the risk that the service crashes/respawns
in an infinite loop because of a connection error.

Change-Id: Ia71b55dab1535ce351310108aaf53304b15ab757
Closes-Bug: 1640169

manila/share/drivers/cephfs/cephfs_native.py

@@ -82,6 +82,11 @@ class CephFSNativeDriver(driver.ShareDriver,):
 
         self.configuration.append_config_values(cephfs_native_opts)
 
+    def check_for_setup_error(self):
+        # NOTE: make sure that we can really connect to the ceph,
+        # otherwise an exception is raised
+        self.volume_client
+
     def _update_share_stats(self):
         stats = self.volume_client.rados.get_cluster_stats()
 

manila/tests/share/drivers/cephfs/test_cephfs_native.py

@@ -449,3 +449,15 @@ class CephFSNativeDriverTestCase(test.TestCase):
                           self._driver.create_share,
                           self._context,
                           self._share)
+
+    def test_check_for_setup_error(self):
+        self._driver.check_for_setup_error()
+        self._driver._volume_client.connect.assert_called_once_with(
+            premount_evict='manila')
+
+    def test_check_for_setup_error_with_connection_error(self):
+        cephfs_native.ceph_module_found = False
+        cephfs_native.ceph_volume_client = None
+
+        self.assertRaises(exception.ManilaException,
+                          self._driver.check_for_setup_error)

releasenotes/notes/bug-1640169-check-ceph-connection-on-setup-c92bde41ced43326.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - Added a check on driver startup for CEPHFS back ends to verify whether
+    the back end is accessible.