Build: https://luci-milo.appspot.com/buildbot/chromeos/x86-zgb-paladin/9107
Failed test results: https://pantheon.corp.google.com/storage/browser/chromeos-autotest-results/103509679-chromeos-test/chromeos6-row2-rack6-host17/debug

Output:

9318.0.0-rc3&force_update=True&pid=2271&host_name=chromeos6-row2-rack6-host17&full_update=False"''
02/26 00:33:41.042 DEBUG|        dev_server:1791| Current CrOS auto-update status: rootfs update
02/26 00:33:51.090 DEBUG|        base_utils:0185| Running 'ssh 100.115.185.227 'curl "http://100.115.185.227:8082/get_au_status?build_name=x86-zgb-paladin/R58-9318.0.0-rc3&force_update=True&pid=2271&host_name=chromeos6-row2-rack6-host17&full_update=False"''
02/26 00:33:52.448 DEBUG|        dev_server:1791| Current CrOS auto-update status: rootfs update
02/26 00:34:02.498 DEBUG|        base_utils:0185| Running 'ssh 100.115.185.227 'curl "http://100.115.185.227:8082/get_au_status?build_name=x86-zgb-paladin/R58-9318.0.0-rc3&force_update=True&pid=2271&host_name=chromeos6-row2-rack6-host17&full_update=False"''
02/26 00:34:03.827 DEBUG|        dev_server:1853| Failed to trigger auto-update process on devserver
02/26 00:34:03.828 DEBUG|        base_utils:0185| Running 'ssh 100.115.185.227 'curl "http://100.115.185.227:8082/handler_cleanup?pid=2271&host_name=chromeos6-row2-rack6-host17"''
02/26 00:34:05.055 DEBUG|        base_utils:0185| Running 'ssh 100.115.185.227 'curl "http://100.115.185.227:8082/collect_cros_au_log?pid=2271&host_name=chromeos6-row2-rack6-host17"''
02/26 00:34:06.424 DEBUG|        dev_server:1685| Saving auto-update logs into /usr/local/autotest/results/hosts/chromeos6-row2-rack6-host17/1105928-provision/20172602002939/autoupdate_logs/CrOS_update_chromeos6-row2-rack6-host17_2271.log
02/26 00:34:06.425 DEBUG|        dev_server:1952| Exception raised on auto_update attempt #1:
 Traceback (most recent call last):
  File "/home/chromeos-test/chromiumos/src/platform/dev/cros_update.py", line 246, in TriggerAU
    self._RootfsUpdate(chromeos_AU)
  File "/home/chromeos-test/chromiumos/src/platform/dev/cros_update.py", line 159, in _RootfsUpdate
    cros_updater.UpdateRootfs()
  File "/home/chromeos-test/chromiumos/chromite/lib/auto_updater.py", line 619, in UpdateRootfs
    raise RootfsUpdateError(error_msg % e)
RootfsUpdateError: Failed to perform rootfs update: DevServerStartupError('Devserver portfile does not exist!',)