Error log:

Traceback (most recent call last):
  File "/build/lakitu-gpu/usr/local/build/autotest/site_utils/test_that.py", line 23, in <module>
    from autotest_lib.server.hosts import factory
  File "/build/lakitu-gpu/usr/local/build/autotest/server/hosts/__init__.py", line 16, in <module>
    from adb_host import ADBHost
  File "/build/lakitu-gpu/usr/local/build/autotest/server/hosts/adb_host.py", line 24, in <module>
    from autotest_lib.server import afe_utils
  File "/build/lakitu-gpu/usr/local/build/autotest/server/afe_utils.py", line 18, in <module>
    AFE = frontend_wrappers.RetryingAFE(timeout_min=5, delay_sec=10)
  File "/build/lakitu-gpu/usr/local/build/autotest/server/cros/dynamic_suite/frontend_wrappers.py", line 66, in __init__
    super(RetryingAFE, self).__init__(**dargs)
  File "/build/lakitu-gpu/usr/local/build/autotest/server/frontend.py", line 497, in __init__
    reply_debug=reply_debug)
  File "/build/lakitu-gpu/usr/local/build/autotest/server/frontend.py", line 76, in __init__
    if not user and utils.is_in_container():
  File "/build/lakitu-gpu/usr/local/build/autotest/client/common_lib/utils.py", line 2487, in is_in_container
    if os.environ['container'] == 'lxc':
  File "/usr/lib64/python2.7/UserDict.py", line 23, in __getitem__
    raise KeyError(key)
KeyError: 'container'


Examples:
https://luci-milo.appspot.com/buildbot/chromeos/lakitu-incremental/15356
https://luci-milo.appspot.com/buildbot/chromeos/lakitu_next-incremental/10929