gnocchi use in devstack is broken

[Matthias Runge]

++/opt/stack/ceilometer/devstack/plugin.sh:configure_gnocchi:167 gnocchi-upgrade
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 567, in _build_master
    ws.require(__requires__)
  File "/usr/local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 884, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 775, in resolve
    raise VersionConflict(dist, req).with_context(dependent_req)
pkg_resources.ContextualVersionConflict: (oslo.policy 3.5.0 (/usr/local/lib/python3.6/site-packages), Requirement.parse('oslo.policy<=3.4.0,>=0.3.0'), {'gnocchi'})

This is caused by https://github.com/gnocchixyz/gnocchi/pull/1088

[Matthias Runge (mrunge)]

so, gnocchi use on devstack will be broken with all projects requiring oslo.policy >= 3.5.0, this is not specific to cinder

[Matthias Runge (mrunge)]

https://github.com/gnocchixyz/gnocchi/issues/1095

[Dr. Jens Harbott (j-harbott)]

Ah, sorry, I mixed up ceilometer and cinder. Still, devstack doesn't use gnocchi, so it isn't affected, it's the ceilometer plugin that needs fixing.

[Matthias Runge (mrunge)]

There is nothing to be done in ceilometer, since gnocchi is currently incompatible with the rest of the stack.

We (as in OpenStack) probably don't want to downgrade oslo.policy.