The openstack Python client may be configured with a YAML file

To do this create a clouds.yaml file.

clouds:
  the-cloud:
    auth:
      auth_url: http://192.168.122.10:5000/
      project_name: demo
      username: demo
      password: 0penstack
    region_name: RegionOne

Then specify the configured cloud using the --os-cloud parameter

openstack --os-cloud the-cloud server list 

(docs.openstack.og) OpenStack Command Line Client / Configuration