Hmm, do you only have a single compute host? It appears that you're trying to resize the instance to the same host it's already on:

2018-06-15 16:23:46.876 7 ERROR nova.compute.manager [req-69050681-be73-48c5-be25-993f05b0b47e e511323a68a740f597880a1b056e3918 28f4e0797d544d758700e5be42aa82c6 - default default] [instance: daa5b10b-0655-4178-9413-66697004d7f8] Error: Unable to migrate instance (daa5b10b-0655-4178-9413-66697004d7f8) to current host (compute6).: UnableToMigrateToSelf: Unable to migrate instance (daa5b10b-0655-4178-9413-66697004d7f8) to current host (compute6).
2018-06-15 16:23:46.876 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8] Traceback (most recent call last):
2018-06-15 16:23:46.876 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]   File "/var/lib/kolla/venv/lib/python2.7/site-packages/nova/compute/manager.py", line 4141, in prep_resize
2018-06-15 16:23:46.876 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]     node, migration, clean_shutdown)
2018-06-15 16:23:46.876 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]   File "/var/lib/kolla/venv/lib/python2.7/site-packages/nova/compute/manager.py", line 4085, in _prep_resize
2018-06-15 16:23:46.876 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]     instance_id=instance.uuid, host=self.host)
2018-06-15 16:23:46.876 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8] UnableToMigrateToSelf: Unable to migrate instance (daa5b10b-0655-4178-9413-66697004d7f8) to current host (compute6).
2018-06-15 16:23:46.876 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8] 

And then due to that, we hit this:

2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [req-69050681-be73-48c5-be25-993f05b0b47e e511323a68a740f597880a1b056e3918 28f4e0797d544d758700e5be42aa82c6 - default default] [instance: daa5b10b-0655-4178-9413-66697004d7f8] Setting instance vm_state to ERROR: IndexError: list index out of range
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8] Traceback (most recent call last):
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]   File "/var/lib/kolla/venv/lib/python2.7/site-packages/nova/compute/manager.py", line 7445, in _error_out_instance_on_exception
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]     yield
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]   File "/var/lib/kolla/venv/lib/python2.7/site-packages/nova/compute/manager.py", line 4162, in prep_resize
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]     filter_properties, host_list)
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]   File "/var/lib/kolla/venv/lib/python2.7/site-packages/nova/compute/manager.py", line 4221, in _reschedule_resize_or_reraise
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]     exception=exc_info[1])
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]   File "/var/lib/kolla/venv/lib/python2.7/site-packages/nova/rpc.py", line 225, in wrapped
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]     return f(*args, **kwargs)
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]   File "/var/lib/kolla/venv/lib/python2.7/site-packages/nova/compute/utils.py", line 367, in notify_about_instance_action
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]     fault, priority = _get_fault_and_priority_from_exc(exception)
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]   File "/var/lib/kolla/venv/lib/python2.7/site-packages/nova/compute/utils.py", line 348, in _get_fault_and_priority_from_exc
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]     exception)
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]   File "/var/lib/kolla/venv/lib/python2.7/site-packages/nova/notifications/objects/exception.py", line 42, in from_exception
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8]     trace = inspect.trace()[-1]
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8] IndexError: list index out of range
2018-06-15 16:23:46.954 7 ERROR nova.compute.manager [instance: daa5b10b-0655-4178-9413-66697004d7f8] 

And from there things spiral out of control. That IndexError is probably what we need to dig into.