# vim /etc/nova/nova.conf
[DEFAULT]
...................................................
instance_build_timeout = 3600
reboot_timeout = 600
running_deleted_instance_action = reap
running_deleted_instance_poll_interval = 1800
running_deleted_instance_timeout = 1800
instance_usage_audit = True
instance_usage_audit_period = hour
notify_on_state_change = vm_and_task_state
notification_driver = messagingv2
block_device_allocate_retries=1200
block_device_allocate_retries_interval=3