Comment 0 for bug 1870087

I have a machine which was failing to connect to the landscape service. In syslog I found this traceback:

Apr 1 03:27:53 maas-1 landscape-client[1538354]: Traceback (most recent call last):
Apr 1 03:27:53 maas-1 landscape-client[1538354]: File "/usr/lib/python3/dist-packages/twisted/python/lockfile.py", line 160, in lock
Apr 1 03:27:53 maas-1 landscape-client[1538354]: symlink(str(os.getpid()), self.name)
Apr 1 03:27:53 maas-1 landscape-client[1538354]: FileExistsError: [Errno 17] File exists: '1538397' -> b'/var/lib/landscape/client/sockets/broker.sock.lock'
Apr 1 03:27:53 maas-1 landscape-client[1538354]: During handling of the above exception, another exception occurred:
Apr 1 03:27:53 maas-1 landscape-client[1538354]: Traceback (most recent call last):
Apr 1 03:27:53 maas-1 landscape-client[1538354]: File "/usr/bin/landscape-broker", line 8, in <module>
Apr 1 03:27:53 maas-1 landscape-client[1538354]: run(sys.argv)
Apr 1 03:27:53 maas-1 landscape-client[1538354]: File "/usr/lib/python3/dist-packages/landscape/client/broker/service.py", line 93, in run
Apr 1 03:27:53 maas-1 landscape-client[1538354]: run_landscape_service(BrokerConfiguration, BrokerService, args)
Apr 1 03:27:53 maas-1 landscape-client[1538354]: File "/usr/lib/python3/dist-packages/landscape/client/service.py", line 115, in run_landscape_service
Apr 1 03:27:53 maas-1 landscape-client[1538354]: startApplication(application, False)
Apr 1 03:27:53 maas-1 landscape-client[1538354]: File "/usr/lib/python3/dist-packages/twisted/application/app.py", line 690, in startApplication
Apr 1 03:27:53 maas-1 landscape-client[1538354]: service.IService(application).startService()
Apr 1 03:27:53 maas-1 landscape-client[1538354]: File "/usr/lib/python3/dist-packages/twisted/application/service.py", line 288, in startService
Apr 1 03:27:53 maas-1 landscape-client[1538354]: service.startService()
Apr 1 03:27:53 maas-1 landscape-client[1538354]: File "/usr/lib/python3/dist-packages/landscape/client/broker/service.py", line 79, in startService
Apr 1 03:27:53 maas-1 landscape-client[1538354]: self.publisher.start()
Apr 1 03:27:53 maas-1 landscape-client[1538354]: File "/usr/lib/python3/dist-packages/landscape/client/amp.py", line 45, in start
Apr 1 03:27:53 maas-1 landscape-client[1538354]: self._port = self._reactor.listen_unix(socket_path, factory)
Apr 1 03:27:53 maas-1 landscape-client[1538354]: File "/usr/lib/python3/dist-packages/landscape/lib/reactor.py", line 228, in listen_unix
Apr 1 03:27:53 maas-1 landscape-client[1538354]: return self._reactor.listenUNIX(socket, factory, wantPID=True)
Apr 1 03:27:53 maas-1 landscape-client[1538354]: File "/usr/lib/python3/dist-packages/twisted/internet/posixbase.py", line 397, in listenUNIX
Apr 1 03:27:53 maas-1 landscape-client[1538354]: p.startListening()
Apr 1 03:27:53 maas-1 landscape-client[1538354]: File "/usr/lib/python3/dist-packages/twisted/internet/unix.py", line 372, in startListening
Apr 1 03:27:53 maas-1 landscape-client[1538354]: if not self.lockFile.lock():
Apr 1 03:27:53 maas-1 landscape-client[1538354]: File "/usr/lib/python3/dist-packages/twisted/python/lockfile.py", line 185, in lock
Apr 1 03:27:53 maas-1 landscape-client[1538354]: kill(int(pid), 0)
Apr 1 03:27:53 maas-1 landscape-client[1538354]: PermissionError: [Errno 1] Operation not permitted

In the sockets directory I saw:

$ sudo ls /var/lib/landscape/client/sockets/ -la
total 8
drwxr-x--- 2 landscape root 4096 Apr 1 03:27 .
drwxr-xr-x 7 landscape root 4096 Apr 1 03:27 ..
srw-rw-rw- 1 landscape landscape 0 Mar 12 01:41 broker.sock
lrwxrwxrwx 1 landscape landscape 3 Mar 12 01:41 broker.sock.lock -> 905

Removing those two files allowed the landscape client to start as normal.

Looks like we need some lockfile cleanup code on start.