restart the containers after the host reboot

Some containers are running in a host. If the host reboots,
all the running containers will be stopped.
It's better to restart them when zun-compute works.

Change-Id: I7442110fc453e0fa8760038ce213689e630347d2
Implements:blueprint restart-container-when-host-reboot

zun/compute/manager.py

@@ -49,10 +49,29 @@ class Manager(periodic_task.PeriodicTasks):
         else:
             self.use_sandbox = False
 
+    def restore_running_container(self, context, container, db_container):
+        if (container.status == consts.RUNNING and
+                db_container.status == consts.STOPPED):
+            try:
+                self.container_reboot(context, container, 10)
+            except Exception:
+                LOG.exception("Failed to complete a restart for container %s",
+                              container.uuid)
+
     def init_containers(self, context):
         containers = objects.Container.list_by_host(context, self.host)
+        db_containers = self.driver.list(context)
+        db_container_map = {container.container_id: container
+                            for container in db_containers
+                            if container.container_id is not None}
         for container in containers:
             self._init_container(context, container)
+            if CONF.compute.resume_container_state and \
+                container.container_id is not None:
+                db_container = db_container_map[container.container_id]
+                self.restore_running_container(context,
+                                               container,
+                                               db_container)
 
     def _init_container(self, context, container):
         '''Initialize this container during zun-compute init.'''

zun/conf/compute.py

@@ -15,6 +15,14 @@
 from oslo_config import cfg
 
 
+compute_opts = [
+    cfg.BoolOpt(
+        'resume_container_state',
+        default=True,
+        help='restart the containers which are running'
+             'before the host reboots.'),
+]
+
 service_opts = [
     cfg.StrOpt(
         'topic',
@@ -47,7 +55,7 @@ Possible values:
 opt_group = cfg.OptGroup(
     name='compute', title='Options for the zun-compute service')
 
-ALL_OPTS = (service_opts + db_opts)
+ALL_OPTS = (service_opts + db_opts + compute_opts)
 
 
 def register_opts(conf):

zun/tests/unit/compute/test_compute_manager.py

@@ -110,6 +110,21 @@ class TestManager(base.TestCase):
         mock_container_start.assert_called_once_with(self.context,
                                                      container)
 
+    @mock.patch.object(manager.Manager, 'container_reboot')
+    @mock.patch.object(Container, 'save')
+    def test_container_reboot_after_host_reboot(self, mock_save,
+                                                mock_container_reboot):
+        container_1 = Container(self.context, **utils.get_test_container())
+        container_2 = Container(self.context, **utils.get_test_container())
+        container_1.status = consts.RUNNING
+        container_2.status = consts.STOPPED
+        self.compute_manager.restore_running_container(self.context,
+                                                       container_1,
+                                                       container_2)
+        mock_container_reboot.assert_called_once_with(self.context,
+                                                      container_1,
+                                                      10)
+
     @mock.patch.object(Container, 'save')
     def test_init_container_retries_start_already(self, mock_save):
         container = Container(self.context, **utils.get_test_container())