Fixes LP688545.

nova/compute/manager.py

@@ -327,6 +327,7 @@ class ComputeManager(manager.Manager):
                 instance_ref["internal_id"])
             return self.driver.get_diagnostics(instance_ref)
 
+    @exception.wrap_exception
     def suspend_instance(self, context, instance_id):
         """suspend the instance with instance_id"""
         context = context.elevated()

nova/db/sqlalchemy/__init__.py

@@ -19,6 +19,25 @@
 """
 SQLAlchemy database backend
 """
+import logging
+import time
+
+from sqlalchemy.exc import OperationalError
+
+from nova import flags
 from nova.db.sqlalchemy import models
 
-models.register_models()
+
+FLAGS = flags.FLAGS
+
+
+for i in xrange(FLAGS.sql_max_retries):
+    if i > 0:
+        time.sleep(FLAGS.sql_retry_interval)
+
+    try:
+        models.register_models()
+        break
+    except OperationalError:
+        logging.exception(_("Data store is unreachable."
+            " Trying again in %d seconds.") % FLAGS.sql_retry_interval)

nova/flags.py

@@ -266,6 +266,8 @@ DEFINE_string('sql_connection',
 DEFINE_string('sql_idle_timeout',
               '3600',
               'timeout for idle sql database connections')
+DEFINE_integer('sql_max_retries', 12, 'sql connection attempts')
+DEFINE_integer('sql_retry_interval', 10, 'sql connection retry interval')
 
 DEFINE_string('compute_manager', 'nova.compute.manager.ComputeManager',
               'Manager for compute')

nova/tests/test_xenapi.py

@@ -250,15 +250,16 @@ class XenAPIVMTestCase(test.TestCase):
 
     def _create_instance(self):
         """Creates and spawns a test instance"""
-        values = {'name': 1, 'id': 1,
-                  'project_id': self.project.id,
-                  'user_id': self.user.id,
-                  'image_id': 1,
-                  'kernel_id': 2,
-                  'ramdisk_id': 3,
-                  'instance_type': 'm1.large',
-                  'mac_address': 'aa:bb:cc:dd:ee:ff'
-                  }
+        values = {
+            'name': 1,
+            'id': 1,
+            'project_id': self.project.id,
+            'user_id': self.user.id,
+            'image_id': 1,
+            'kernel_id': 2,
+            'ramdisk_id': 3,
+            'instance_type': 'm1.large',
+            'mac_address': 'aa:bb:cc:dd:ee:ff'}
         instance = db.instance_create(values)
         self.conn.spawn(instance)
         return instance