On`integration-cumin.integration.eqiad.wmflabs`:
```
$ sudo cumin --force 'name:docker' 'docker ps -a'
Caught InvalidQueryError exception: Default backend 'openstack' is not registered: {
'F': Backend(keyword='F', name='cumin_file_backend', cls=<class 'cumin_file_backend.HostsFileQuery'>),
'D': Backend(keyword='D', name='direct', cls=<class 'cumin.backends.direct.DirectQuery'>),
'P': Backend(keyword='P', name='puppetdb', cls=<class 'cumin.backends.puppetdb.PuppetDBQuery'>),
'K': Backend(keyword='K', name='knownhosts', cls=<class 'cumin.backends.knownhosts.KnownHostsQuery'>)}
```
/etc/cumin/config.yaml has:
```
default_backend: openstack
plugins:
backends:
- cumin_file_backend
```
Via strace it does open openstack.py but that is apparently not enabled in the configuration :]
-----
//The original issue below has been fixed by https://gerrit.wikimedia.org/r/#/c/419131/ //
```
$ sudo cumin --force 'name:docker' 'docker ps -a'
Caught CuminError exception: Unable to import backend 'cumin_file_backend': No module named 'cumin_file_backend'
```
From my bash history, it was still working on 2018-02-14 09:41:00.
Cumin got upgraded via unattended-upgrade:
```
Start-Date: 2018-02-20 06:51:07
Commandline: /usr/bin/unattended-upgrade
Install: ...
Upgrade: ..., cumin:amd64 (2.0.0-1, 3.0.1-1)
```
The issue is the file backend (introduced by 88c43843c3d886b90b5756ad7fb6a7ee4d84da7e for T185967) is installed /usr/local/lib/python2.7/dist-packages/cumin_file_backend.py . Cumin now uses python3 and thus it is unable to lookup the file :-(
May I suggest that cumin_file_backend to be included in cumin itself instead of being provided by puppet? :]