Random "paramiko.SSHException: No existing session" exceptions

[Paul Sokolovsky]

After rebooting my box, I'm getting:

Traceback (most recent call last):
  File "gerritconnection.py", line 105, in <module>
    c.init_client()
  File "gerritconnection.py", line 33, in init_client
    key_filename=self.ssh_key_file)
  File "/usr/lib/pymodules/python2.6/paramiko/client.py", line 327, in connect
    self._auth(username, password, pkey, key_filenames, allow_agent, look_for_keys)
  File "/usr/lib/pymodules/python2.6/paramiko/client.py", line 481, in _auth
    raise saved_exception
paramiko.SSHException: No existing session

It worked well before. Googling for it turns out posts like: http://stackoverflow.com/questions/6832248/paramiko-no-existing-session-exception (problem reported, solution not posted). Bad sign.

[Paul Sokolovsky (pfalcon)]

This is apparently happens due do weird interaction with ssh keyagent.

[Paul Sokolovsky (pfalcon)]

I mean on another reboot, and activating key while running gerritconnection.py in test mode (not some other auth-requesting app), it goes thru. Maybe it gets keys in unexpected order (and can't handle well trying few keys) or something.

All in all, we may want to consider disabling any auth methods except via specified key file (that doesn't help during debugging of course, so hitting issues like this neither ;-) ).

[Frans Gifford (fgiff)]

Looks like this was fixed by http://bazaar.launchpad.net/~linaro-android-bot-maintainers/linaro-android-bot-review/trunk/revision/63

[Paul Sokolovsky (pfalcon)]

To be exact, this was fixed by requiring explicit SSH key file. So, even you'll want to do debugging with local user, you'll need to provide path to your key. Using other keysources (liek ssh-agent) is not really disabled, but if more issues arise, we might consider that.