Problem: UCS@school ID connector fails to start if old pid-file exists

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#1

Problem

If the service cannot be started by the ID connector, it may be due to unprocessed pid file blocking the service. Among other things, this can be caused by a power failure in the system.

The Bug 54640 causes this misbehavior.

You will get this output if you check the container log with:
univention-app logs ucsschool-id-connector

This init-script assumes that old pid-files are removed and fails to start once a remnant exists. This may be tha case on unclean shutdown.

/etc/init.d # ./ucsschool-id-connector start
 * Starting UCS@school ID Connector ...
Traceback (most recent call last):
  File "/ucsschool-id-connector/src/queue_management", line 170, in <module>
    _start()
  File "/ucsschool-id-connector/src/queue_management", line 151, in _start
    service.start()
  File "/usr/lib/python3.8/site-packages/service/__init__.py", line 461, in start
    raise ValueError('Daemon is already running at PID %d.' % pid)
ValueError: Daemon is already running at PID 146.                                                                                                                                                                                                       [ !! ]
 * ERROR: ucsschool-id-connector failed to start
/etc/init.d # cat /tmp/IDConnectorService.pid
146
/etc/init.d # 
/etc/init.d # pgrep IDConnectorService
/etc/init.d # rm /tmp/IDConnectorService.pid 
/etc/init.d # ./ucsschool-id-connector start
 * Starting UCS@school ID Connector ...
Started IDConnectorService daemon.                                                                                                                                                                                                                      [ ok ]
/etc/init.d # ./ucsschool-id-connector status
 * status: started

Solution

Connect into the container and check if an old PID File exist.

univention-app shell ucsschool-id-connector

/ucsschool-id-connector # ls -lah  /tmp/
drwxrwxrwx    1 root     root        4.0K Dec 10 16:36 .
drwxr-xr-x    1 root     root        4.0K Dec 9 14:14 ..
-rw-r--r--    1 root     root           4 Dec 10 16:36 IDConnectorService.pid

So there is an old PID File exist, go further with reset the state in the container.

  1. /etc/init.d/ucsschool-id-connector stop
  2. /etc/init.d/ucsschool-id-connector zap
  3. /etc/init.d/ucsschool-id-connector start

Connect out of the container with cntr+d and check again the container logs, to see that the ID-Connector works again and the error is fixed.
univention-app logs ucsschool-id-connector

#2
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