root@controller:/etc/kolla# ansible --verison
Traceback (most recent call last):
  File "/usr/local/bin/ansible", line 36, in <module>
    from ansible.runner import Runner
  File "/usr/local/lib/python2.7/dist-packages/ansible/runner/__init__.py", line 37, in <module>
    import ansible.inventory
  File "/usr/local/lib/python2.7/dist-packages/ansible/inventory/__init__.py", line 26, in <module>
    from ansible.inventory.ini import InventoryParser
  File "/usr/local/lib/python2.7/dist-packages/ansible/inventory/ini.py", line 21, in <module>
    from ansible.inventory.host import Host
  File "/usr/local/lib/python2.7/dist-packages/ansible/inventory/host.py", line 19, in <module>
    from ansible import utils
  File "/usr/local/lib/python2.7/dist-packages/ansible/utils/__init__.py", line 27, in <module>
    from ansible import errors
  File "/usr/local/lib/python2.7/dist-packages/ansible/errors/__init__.py", line 29, in <module>
    from ansible.utils.unicode import to_unicode, to_str
ImportError: cannot import name to_str