I am using OpenStack Mitaka on Ubuntu server and using Heat template to create my instances. My stack creation takes up to 3 hours, so I set the parameter "reauthentication_auth_method=trusts" in "/etc/heat/heat.conf" file to allow reauthentication on token expiry due to long-running tasks , and also give the timeout greater than 3 hours when I launched my stack. I am re-creating the stack for my testing. Sometimes my stack creation has been completed successfully, but sometimes I get the "resource could not be found (HTTP 404)" error after an hour later stack creation started. When I check the heat-engine.log, I saw the error given below. Do I need to set any other parameter in configuration file?

2017-01-12 02:45:32.805 126261 INFO heat.engine.resource [-] CREATE: Server "App-2" [8255723a-c9db-4835-94f1-348f1c72c96f] Stack "my_stack" [373df5cc-43d4-4bef-ba64-072a6fa3a546] 
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource Traceback (most recent call last):
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource   File "/usr/lib/python2.7/dist-packages/heat/engine/resource.py", line 708, in _action_recorder

2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource     yield
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource   File "/usr/lib/python2.7/dist-packages/heat/engine/resource.py", line 779, in _do_action

2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource     yield self.action_handler_task(action, args=handler_args)
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource   File "/usr/lib/python2.7/dist-packages/heat/engine/scheduler.py", line 314, in wrapper
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource     step = next(subtask)

2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource   File "/usr/lib/python2.7/dist-packages/heat/engine/resource.py", line 753, in action_handler_task
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource     while not check(handler_data):
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource   File "/usr/lib/python2.7/dist-packages/heat/engine/resources/openstack/nova/server.py", line 872, in check_create_complete
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource     check = self.client_plugin()._check_active(server_id)
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource   File "/usr/lib/python2.7/dist-packages/heat/engine/clients/os/nova.py", line 202, in _check_active

2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource     server = self.fetch_server(server)
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource   File "/usr/lib/python2.7/dist-packages/heat/engine/clients/os/nova.py", line 131, in fetch_server
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource     server = self.client().servers.get(server_id)
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource   File "/usr/lib/python2.7/dist-packages/novaclient

/v2/servers.py", line 676, in get
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource     return self._get("/servers/%s" % base.getid(server), "server")
2017-01-12 02:45:32.805 126261 ERROR heat.engine.resource   File "/usr/lib/python2.7/dist-packages/novaclient/base.py", line 339, in _get
2017-01-12 02:45:32.805 126261 ERROR heat ...