No module named 'tornado.locks' when starting salt minion

[Patric]

Hi,

I get the following exception when I try to start the Salt Minion:

Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/utils/sdb.py", line 14, in <module>
Mar 07 12:18:11 myserver salt-minion[73415]:     import salt.loader
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/loader.py", line 26, in <module>
Mar 07 12:18:11 myserver salt-minion[73415]:     import salt.utils.event
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/utils/event.py", line 83, in <module>
Mar 07 12:18:11 myserver salt-minion[73415]:     import salt.transport.ipc
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/transport/ipc.py", line 21, in <module>
Mar 07 12:18:11 myserver salt-minion[73415]:     from tornado.locks import Semaphore
Mar 07 12:18:11 myserver salt-minion[73415]: ModuleNotFoundError: No module named 'tornado.locks'
Mar 07 12:18:11 myserver salt-minion[73415]: Process Process-1:
Mar 07 12:18:11 myserver salt-minion[73415]: Traceback (most recent call last):
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/utils/parsers.py", line 200, in parse_args
Mar 07 12:18:11 myserver salt-minion[73415]:     process_option_func()
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/utils/parsers.py", line 546, in process_config_dir
Mar 07 12:18:11 myserver salt-minion[73415]:     self.config.update(self.setup_config())
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/utils/parsers.py", line 1773, in setup_config
Mar 07 12:18:11 myserver salt-minion[73415]:     ignore_config_errors=False)
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/config/__init__.py", line 2212, in minion_config
Mar 07 12:18:11 myserver salt-minion[73415]:     apply_sdb(opts)
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/config/__init__.py", line 2346, in apply_sdb
Mar 07 12:18:11 myserver salt-minion[73415]:     import salt.utils.sdb
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/utils/sdb.py", line 14, in <module>
Mar 07 12:18:11 myserver salt-minion[73415]:     import salt.loader
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/loader.py", line 26, in <module>
Mar 07 12:18:11 myserver salt-minion[73415]:     import salt.utils.event
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/utils/event.py", line 83, in <module>
Mar 07 12:18:11 myserver salt-minion[73415]:     import salt.transport.ipc
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/transport/ipc.py", line 21, in <module>
Mar 07 12:18:11 myserver salt-minion[73415]:     from tornado.locks import Semaphore
Mar 07 12:18:11 myserver salt-minion[73415]: ModuleNotFoundError: No module named 'tornado.locks'
Mar 07 12:18:11 myserver salt-minion[73415]: During handling of the above exception, another exception occurred:
Mar 07 12:18:11 myserver salt-minion[73415]: Traceback (most recent call last):
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3.6/multiprocessing/process.py", line 258, in _bootstrap
Mar 07 12:18:11 myserver salt-minion[73415]:     self.run()
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3.6/multiprocessing/process.py", line 93, in run
Mar 07 12:18:11 myserver salt-minion[73415]:     self._target(*self._args, **self._kwargs)
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/scripts.py", line 138, in minion_process
Mar 07 12:18:11 myserver salt-minion[73415]:     minion.start()
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/cli/daemons.py", line 342, in start
Mar 07 12:18:11 myserver salt-minion[73415]:     super(Minion, self).start()
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/utils/parsers.py", line 1039, in start
Mar 07 12:18:11 myserver salt-minion[73415]:     self.prepare()
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/cli/daemons.py", line 243, in prepare
Mar 07 12:18:11 myserver salt-minion[73415]:     super(Minion, self).prepare()
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/utils/parsers.py", line 1036, in prepare
Mar 07 12:18:11 myserver salt-minion[73415]:     self.parse_args()
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3/dist-packages/salt/utils/parsers.py", line 205, in parse_args
Mar 07 12:18:11 myserver salt-minion[73415]:     process_option_func, traceback.format_exc(err)
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3.6/traceback.py", line 167, in format_exc
Mar 07 12:18:11 myserver salt-minion[73415]:     return "".join(format_exception(*sys.exc_info(), limit=limit, chain=chain))
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3.6/traceback.py", line 121, in format_exception
Mar 07 12:18:11 myserver salt-minion[73415]:     type(value), value, tb, limit=limit).format(chain=chain))
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3.6/traceback.py", line 509, in __init__
Mar 07 12:18:11 myserver salt-minion[73415]:     capture_locals=capture_locals)
Mar 07 12:18:11 myserver salt-minion[73415]:   File "/usr/lib/python3.6/traceback.py", line 338, in extract
Mar 07 12:18:11 myserver salt-minion[73415]:     if limit >= 0:
Mar 07 12:18:11 myserver salt-minion[73415]: TypeError: '>=' not supported between instances of 'ModuleNotFoundError' and 'int'
Mar 07 12:18:11 myserver systemd[1]: salt-minion.service: Main process exited, code=exited, status=1/FAILURE
Mar 07 12:18:11 myserver systemd[1]: salt-minion.service: Failed with result 'exit-code'.

My environment:

# lsb_release -a
No LSB modules are available.
Distributor ID:    Ubuntu
Description:    Ubuntu 18.04.1 LTS
Release:    18.04
Codename:    bionic

# dpkg -l |grep salt
ii  salt-common                          2017.7.4+dfsg1-1
ii  salt-minion                          2017.7.4+dfsg1-1    

The python3-tornado package is installed.

I also tried to

- purge the salt packages

- rm -rf /var/lib/salt/ /etc/salt

- and reinstall the salt packages.

Unfortnuately this didn't help.

Any ideas?

Best,

Patric