maas rackd tftp bootstrap.py: 'Nonetype' object has no attribute 'stopListening'

[Dmitrii Shcherbakov]

Encountered in the wild. This is a 3-region 2-rack controller MAAS deployment (as per our "automation engine").

2017-10-22 23:34:30 provisioningserver.dhcp.detect: [info] External DHCP server(s) discovered on interface 'br0': 10.30.20.2
2017-10-22 23:34:40 provisioningserver.rackdservices.dhcp_probe_service: [info] External DHCP probe complete.
2017-10-22 23:36:27 provisioningserver.rackdservices.tftp: [info] pxelinux.0 requested by 52:54:00:46:4a:52
2017-10-22 23:36:27 provisioningserver.rackdservices.tftp: [info] ldlinux.c32 requested by 52:54:00:46:4a:52
2017-10-22 23:36:27 provisioningserver.rackdservices.tftp: [info] pxelinux.cfg/71a72332-067c-904b-80c5-7f6e07dc18fe requested by 52:54:00:46:4a:52
2017-10-22 23:36:27 provisioningserver.rackdservices.tftp: [info] pxelinux.cfg/01-52-54-00-46-4a-52 requested by 52:54:00:46:4a:52
2017-10-22 23:36:27 provisioningserver.rackdservices.tftp: [info] ubuntu/amd64/ga-16.04/xenial/daily/boot-kernel requested by 52:54:00:46:4a:52
2017-10-22 23:36:28 provisioningserver.rackdservices.tftp: [info] ubuntu/amd64/ga-16.04/xenial/daily/boot-initrd requested by 52:54:00:46:4a:52
2017-10-22 23:36:38 provisioningserver.rackdservices.tftp: [info] pxelinux.0 requested by 52:54:00:64:64:20
2017-10-22 23:36:38 provisioningserver.rackdservices.tftp: [info] ldlinux.c32 requested by 52:54:00:64:64:20
2017-10-22 23:36:38 provisioningserver.rackdservices.tftp: [info] pxelinux.cfg/f2f414f0-4572-9f40-aa2a-2993f5a423a8 requested by 52:54:00:64:64:20
2017-10-22 23:36:38 provisioningserver.rackdservices.tftp: [info] pxelinux.cfg/01-52-54-00-64-64-20 requested by 52:54:00:64:64:20
2017-10-22 23:36:38 provisioningserver.rackdservices.tftp: [info] pxelinux.cfg/01-52-54-00-64-64-20 requested by 52:54:00:64:64:20
2017-10-22 23:36:38 provisioningserver.rackdservices.tftp: [info] ubuntu/amd64/ga-16.04/xenial/daily/boot-kernel requested by 52:54:00:64:64:20
2017-10-22 23:36:39 provisioningserver.rackdservices.tftp: [info] ubuntu/amd64/ga-16.04/xenial/daily/boot-initrd requested by 52:54:00:64:64:20
2017-10-22 23:39:46 provisioningserver.rackdservices.tftp: [info] pxelinux.0 requested by 52:54:00:64:64:20
2017-10-22 23:39:46 provisioningserver.rackdservices.tftp: [info] ldlinux.c32 requested by 52:54:00:64:64:20
2017-10-22 23:39:46 provisioningserver.rackdservices.tftp: [info] pxelinux.cfg/f2f414f0-4572-9f40-aa2a-2993f5a423a8 requested by 52:54:00:64:64:20
2017-10-22 23:39:46 provisioningserver.rackdservices.tftp: [info] pxelinux.cfg/01-52-54-00-64-64-20 requested by 52:54:00:64:64:20
2017-10-22 23:39:46 provisioningserver.rackdservices.tftp: [info] pxelinux.cfg/01-52-54-00-64-64-20 requested by 52:54:00:64:64:20
2017-10-22 23:39:46 provisioningserver.rackdservices.tftp: [info] chain.c32 requested by 52:54:00:64:64:20
2017-10-22 23:39:46 provisioningserver.rackdservices.tftp: [info] libcom32.c32 requested by 52:54:00:64:64:20
2017-10-22 23:39:46 provisioningserver.rackdservices.tftp: [info] libutil.c32 requested by 52:54:00:64:64:20
2017-10-22 23:39:52 -: [critical] Unhandled Error
        Traceback (most recent call last):
          File "/usr/lib/python3/dist-packages/twisted/application/app.py", line 364, in startReactor
            self.config, oldstdout, oldstderr, self.profiler, reactor)
          File "/usr/lib/python3/dist-packages/twisted/application/app.py", line 285, in runReactorWithLogging
            reactor.run()
          File "/usr/lib/python3/dist-packages/twisted/internet/base.py", line 1194, in run
            self.mainLoop()
          File "/usr/lib/python3/dist-packages/twisted/internet/base.py", line 1203, in mainLoop
            self.runUntilCurrent()
        --- <exception caught here> ---
          File "/usr/lib/python3/dist-packages/twisted/internet/base.py", line 825, in runUntilCurrent
            call.func(*call.args, **call.kw)
          File "/usr/lib/python3/dist-packages/tftp/bootstrap.py", line 207, in timedOut
            self.cancel()
          File "/usr/lib/python3/dist-packages/tftp/bootstrap.py", line 202, in cancel
            self.transport.stopListening()
        builtins.AttributeError: 'NoneType' object has no attribute 'stopListening'

ubuntu@jkt01z00infr001:~$ dpkg -l '*maas*'
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-=======================================-========================-========================-====================================================================================
un maas <none> <none> (no description available)
ii maas-cli 2.2.2-6099-g8751f91-0ubu all MAAS client and command-line interface
un maas-cluster-controller <none> <none> (no description available)
ii maas-common 2.2.2-6099-g8751f91-0ubu all MAAS server common files
ii maas-dhcp 2.2.2-6099-g8751f91-0ubu all MAAS DHCP server
ii maas-dns 2.2.2-6099-g8751f91-0ubu all MAAS DNS server
ii maas-proxy 2.2.2-6099-g8751f91-0ubu all MAAS Caching Proxy
ii maas-rack-controller 2.2.2-6099-g8751f91-0ubu all Rack Controller for MAAS
ii maas-region-api 2.2.2-6099-g8751f91-0ubu all Region controller API service for MAAS
ii maas-region-controller 2.2.2-6099-g8751f91-0ubu all Region Controller for MAAS
un maas-region-controller-min <none> <none> (no description available)
un python-django-maas <none> <none> (no description available)
un python-maas-client <none> <none> (no description available)
un python-maas-provisioningserver <none> <none> (no description available)
ii python3-django-maas 2.2.2-6099-g8751f91-0ubu all MAAS server Django web framework (Python 3)
ii python3-maas-client 2.2.2-6099-g8751f91-0ubu all MAAS python API client (Python 3)
ii python3-maas-provisioningserver 2.2.2-6099-g8751f91-0ubu all MAAS server provisioning libraries (Python 3)

[Dmitrii Shcherbakov (dmitriis)]

May be related to https://bugs.launchpad.net/maas/+bug/1724677 but does not seem to be a duplicate. This looks like an error handling issue.