Make periodic task spacing configurable

Change-Id: I1e35b3538e8656756588e2b94a02756704ccf76b
Closes-Bug: #1745077

zun/conf/services.py

@@ -26,8 +26,24 @@ periodic_opts = [
                default=180,
                help='Max interval size between periodic tasks execution in '
                     'seconds.'),
+    cfg.IntOpt('sync_container_state_interval',
+               default=60,
+               help="""
+Interval to sync container states between the database and the docker.
+
+The interval that Zun checks the actual container state and
+the state that Zun has recorded in its database. If they are inconsistent,
+Zun will update the database according to the actual container state.
+
+Possible values:
+* 0: Will run at the default periodic interval.
+* Any value < 0: Disables the option.
+* Any positive integer in seconds.
+
+"""),
 ]
 
+
 ALL_OPTS = (periodic_opts)
 
 

zun/service/periodic.py

@@ -17,9 +17,12 @@ from oslo_log import log
 from oslo_service import periodic_task
 
 from zun.common import context
+import zun.conf
 from zun.container import driver
 from zun import objects
 
+CONF = zun.conf.CONF
+
 LOG = log.getLogger(__name__)
 
 
@@ -39,7 +42,8 @@ class ContainerStateSyncPeriodicJob(periodic_task.PeriodicTasks):
             conf.container_driver)
         super(ContainerStateSyncPeriodicJob, self).__init__(conf)
 
-    @periodic_task.periodic_task(run_immediately=True)
+    @periodic_task.periodic_task(spacing=CONF.sync_container_state_interval,
+                                 run_immediately=True)
     @set_context
     def sync_container_state(self, ctx):
         LOG.debug('Start syncing container states.')