Retry Coordinator start indefinitely

Change-Id: Iab9a131bf2b606431033236ec40dcda655a9ee78
Closes-Bug: 1514602

designate/coordination.py

@@ -17,6 +17,7 @@
 # under the License.
 
 import math
+import time
 import uuid
 
 from oslo_config import cfg
@@ -79,12 +80,17 @@ class CoordinationMixin(object):
         super(CoordinationMixin, self).start()
 
         if self._coordinator is not None:
-            self._coordinator.start()
+            while not self._coordination_started:
+                try:
+                    self._coordinator.start()
+                    self._coordinator.create_group(self.service_name)
+                    self._coordinator.join_group(self.service_name)
+                    self._coordination_started = True
 
-            self._coordinator.create_group(self.service_name)
-            self._coordinator.join_group(self.service_name)
-
-            self._coordination_started = True
+                except Exception:
+                    LOG.warn(_LW("Failed to start Coordinator:"),
+                             exc_info=True)
+                    time.sleep(15)
 
     def stop(self):
         if self._coordinator is not None:

designate/tests/test_coordination.py

@@ -47,7 +47,7 @@ class TestCoordinationMixin(TestCase):
                       service._coordinator.get_groups().get())
         self.assertIn(service._coordination_id.encode('utf-8'),
                       service._coordinator.get_members(
-                            service.service_name).get())
+                          service.service_name).get())
         service.stop()
 
     def test_stop(self):