Fix postgresql database creation failures from prepare func

postgresql needs to restart during the bootstrap, but the postgres
driver still reports the healthy status.

this commit resets the healthy_counts when status is not healthy,
and make state_healthy_counts configurable.

Change-Id: I746b86326790dbc667f4f0d6dabcd1a656502273

releasenotes/notes/fix-postgresql-database-create-failed-abd4f99cc7dde44c.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    Fix potential PostgreSQL database creation failures from the instance create API

trove/common/cfg.py

@@ -201,6 +201,8 @@ common_opts = [
                     'change.'),
     cfg.IntOpt('state_change_poll_time', default=3,
                help='Interval between state change poll requests (seconds).'),
+    cfg.IntOpt('state_healthy_counts', default=5,
+               help='consecutive success db connections for status HEALTHY'),
     cfg.IntOpt('agent_heartbeat_time', default=10,
                help='Maximum time (in seconds) for the Guest Agent to reply '
                     'to a heartbeat request.'),

trove/guestagent/datastore/service.py

@@ -290,15 +290,15 @@ class BaseDbStatus(object):
         # outside.
         loop = True
 
-        # We need 3 (by default) consecutive success db connections for status
+        # We need 5 (by default) consecutive success db connections for status
         # 'HEALTHY'
         healthy_count = 0
-
+        state_healthy_counts = CONF.state_healthy_counts - 1
         while loop:
             self.status = self.get_actual_db_status()
             if self.status == status:
                 if (status == service_status.ServiceStatuses.HEALTHY and
-                        healthy_count < 2):
+                        healthy_count < state_healthy_counts):
                     healthy_count += 1
                     time.sleep(CONF.state_change_poll_time)
                     continue
@@ -310,7 +310,8 @@ class BaseDbStatus(object):
             # should we remain in this loop? this is the thing
             # that emulates the do-while construct.
             loop = (time.time() < end_time)
-
+            # reset the healthy_count
+            healthy_count = 0
             # no point waiting if our time is up and we're
             # just going to error out anyway.
             if loop: