Virtual Environments¶

Ansible Control Host¶

The kolla-ansible python package and its dependencies may be installed in a python virtual environment on the Ansible control host. For example:

virtualenv /path/to/venv
source /path/to/venv/bin/activate
pip install -U pip
pip install kolla-ansible
deactivate

It may be advantageous to also install Ansible in the virtual environment.

source /path/to/venv/bin/activate
(venv) pip install ansible
(venv) deactivate

To use the virtual environment, it should first be activated:

source /path/to/venv/bin/activate
(venv) kolla-ansible --help

The virtual environment can be deactivated when necessary:

(venv) deactivate

Note that the use of a virtual environment on the Ansible control host does not imply that a virtual environment will be used for execution of Ansible modules on the target hosts.

Target Hosts¶

Ansible supports remote execution of modules in a python virtual environment via the ansible_python_interpreter variable. This may be configured to be the path to a python interpreter installed in a virtual environment. For example:

ansible_python_interpreter: /path/to/venv/bin/python

Note that ansible_python_interpreter cannot be templated.

Kolla-ansible provides support for creating a python virtual environment on the target hosts as part of the bootstrap-servers command. The path to the virtualenv is configured via the virtualenv variable, and access to site-packages is controlled via virtualenv_site_packages. Typically we will need to enable use of system site-packages from within this virtualenv, to support the use of modules such as yum, apt, and selinux, which are not available on PyPI.

When executing kolla-ansible commands other than bootstrap-servers, the variable ansible_python_interpreter should be set to the python interpreter installed in virtualenv.