Zero out SolidFire capacity when unreachable

If for some reason connectivity to the cluster goes down, we just return the
cached capacity info.  Then the scheduler still sees the cluster as an
available resource in the pool.

This change detects connectivity issues during the get_cluster_stats call and
if the call fails, we report 0 available capacity to keep create calls from
being scheduled to the cluster.

Change-Id: I3f730e140c2b61fdd407c90b134916108312278a
Closes-Bug: #1398877

cinder/tests/unit/volume/drivers/solidfire/test_solidfire.py

@@ -823,6 +823,18 @@ class SolidFireVolumeTestCase(test.TestCase):
         self.assertEqual(99.0, sfv.cluster_stats['free_capacity_gb'])
         self.assertEqual(100.0, sfv.cluster_stats['total_capacity_gb'])
 
+    def test_update_cluster_status_mvip_unreachable(self):
+        self.mock_object(solidfire.SolidFireDriver,
+                         '_issue_api_request',
+                         self.fake_issue_api_request)
+        sfv = solidfire.SolidFireDriver(configuration=self.configuration)
+        with mock.patch.object(sfv,
+                               '_issue_api_request',
+                               side_effect=self.fake_issue_api_request_fails):
+            sfv._update_cluster_status()
+            self.assertEqual(0, sfv.cluster_stats['free_capacity_gb'])
+            self.assertEqual(0, sfv.cluster_stats['total_capacity_gb'])
+
     def test_manage_existing_volume(self):
         external_ref = {'name': 'existing volume', 'source-id': 5}
         testvol = {'project_id': 'testprjid',

cinder/volume/drivers/solidfire.py

@@ -1696,14 +1696,6 @@ class SolidFireDriver(san.SanISCSIDriver):
         """Retrieve status info for the Cluster."""
         params = {}
 
-        # NOTE(jdg): The SF api provides an UNBELIEVABLE amount
-        # of stats data, this is just one of the calls
-        results = self._issue_api_request('GetClusterCapacity', params)
-
-        results = results['result']['clusterCapacity']
-        free_capacity = (
-            results['maxProvisionedSpace'] - results['usedSpace'])
-
         data = {}
         backend_name = self.configuration.safe_get('volume_backend_name')
         data["volume_backend_name"] = backend_name or self.__class__.__name__
@@ -1711,19 +1703,29 @@ class SolidFireDriver(san.SanISCSIDriver):
         data["driver_version"] = self.VERSION
         data["storage_protocol"] = 'iSCSI'
         data['consistencygroup_support'] = True
-        # TODO(jdg):  should we have a "replication_status" that includes
-        # enabled, disabled, failed-over, error ?
         data['replication_enabled'] = self.replication_enabled
         if self.replication_enabled:
             data['replication'] = 'enabled'
         data['active_cluster_mvip'] = self.active_cluster_info['mvip']
+        data['reserved_percentage'] = self.configuration.reserved_percentage
+        data['QoS_support'] = True
+
+        try:
+            results = self._issue_api_request('GetClusterCapacity', params)
+        except exception.SolidFireAPIException:
+            data['total_capacity_gb'] = 0
+            data['free_capacity_gb'] = 0
+            self.cluster_stats = data
+            return
+
+        results = results['result']['clusterCapacity']
+        free_capacity = (
+            results['maxProvisionedSpace'] - results['usedSpace'])
 
         data['total_capacity_gb'] = (
             float(results['maxProvisionedSpace'] / units.Gi))
 
         data['free_capacity_gb'] = float(free_capacity / units.Gi)
-        data['reserved_percentage'] = self.configuration.reserved_percentage
-        data['QoS_support'] = True
         data['compression_percent'] = (
             results['compressionPercent'])
         data['deduplicaton_percent'] = (