Traceback (most recent call last):
  File "/usr/local/autotest/server/hosts/cros_host.py", line 920, in machine_install
    update_url, force_update, updater)
  File "/usr/local/autotest/server/hosts/cros_host.py", line 498, in _try_stateful_update
    self.prepare_for_update()
  File "/usr/local/autotest/server/hosts/jetstream_host.py", line 90, in prepare_for_update
    except AutoservRunError:
NameError: global name 'AutoservRunError' is not defined

The test started failing around June 14th,
https://tests.corp.google.com/invocations?searchFor=network_WiFi_UpdateRouter%20lars


After throwing the name error, the server tried to reboot the router and tries to ssh back which it fails. So the test fails with  "Host did not return from reboot" Error. 

07/19 01:54:52.797 INFO |        server_job:0206| 	START	----	reboot	timestamp=1500454492	localtime=Jul 19 01:54:52	
07/19 01:54:52.799 INFO |        server_job:0206| 		GOOD	----	reboot.start	timestamp=1500454492	localtime=Jul 19 01:54:52	

07/19 01:54:53.504 DEBUG|          ssh_host:0296| Running (ssh) 'if [ -f '/proc/sys/kernel/random/boot_id' ]; then cat '/proc/sys/kernel/random/boot_id'; else echo 'no boot_id available'; fi' from 'wait_for_restart|wait_down|get_boot_id|run|wrapper|run_very_slowly'
07/19 01:54:53.826 DEBUG|             utils:0280| [stdout] d8e63aec-2b7c-4654-b6da-04d9e172bdf0
07/19 01:54:54.858 DEBUG|          ssh_host:0296| Running (ssh) 'if [ -f '/proc/sys/kernel/random/boot_id' ]; then cat '/proc/sys/kernel/random/boot_id'; else echo 'no boot_id available'; fi' from 'wait_for_restart|wait_down|get_boot_id|run|wrapper|run_very_slowly'
07/19 01:55:27.335 DEBUG|             utils:0280| [stdout] 08d7cc50-2ded-4744-b95a-224776d4ead2
07/19 01:55:27.343 DEBUG|      abstract_ssh:0684| Host chromeos9-row1-cart1-host4-router now has boot_id 08d7cc50-2ded-4744-b95a-224776d4ead2 and so must have rebooted
07/19 01:55:27.366 DEBUG|          ssh_host:0296| Running (ssh) 'true' from 'wait_up|is_up|ssh_ping|run|wrapper|run_very_slowly'


Running (ssh) '{ ps -e || ps; } | grep 'ap-controller'' from 'wait_for_restart|wait_up|are_wait_up_processes_up|run|wrapper|run_very_slowly'
07/19 02:03:27.360 DEBUG|      abstract_ssh:0601| Host chromeos9-row1-cart1-host4-router is still down after waiting 480 seconds
07/19 02:03:27.362 INFO |        server_job:0206| 		ABORT	----	reboot.verify	timestamp=1500455007	localtime=Jul 19 02:03:27	Host did not return from reboot
07/19 02:03:27.364 INFO |        server_job:0206| 	END FAIL	----	reboot	timestamp=1500455007	localtime=Jul 19 02:03:27	Host did not return from reboot
  Traceback (most recent call last):
    File "/usr/local/autotest/server/server_job.py", line 1062, in run_op
      op_func()
    File "/usr/local/autotest/server/hosts/remote.py", line 160, in reboot
      **dargs)
    File "/usr/local/autotest/server/hosts/remote.py", line 229, in wait_for_restart
      self.log_op(self.OP_REBOOT, op_func)
    File "/usr/local/autotest/client/common_lib/hosts/base_classes.py", line 548, in log_op
      op_func()
    File "/usr/local/autotest/server/hosts/remote.py", line 228, in op_func
      super(RemoteHost, self).wait_for_restart(timeout=timeout, **dargs)
    File "/usr/local/autotest/client/common_lib/hosts/base_classes.py", line 309, in wait_for_restart
      raise error.AutoservRebootError("Host did not return from reboot")
  AutoservRebootError: Host did not return from reboot