Support virtualenv installation in baremetal role

Installing python packages directly to the system site-packages can
cause various problems, in particular when pip overwrites a system
package. Python virtualenvs are one solution to this issue, as they
allow python packages to be installed in an isolated environment.

This change adds support to the baremetal role for installing python
dependencies in a virtualenv. 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.

The path to the virtualenv is configured via the 'virtualenv' variable,
and access to site-packages is controlled via
'virtualenv_site_packages'.

When executing other kolla-ansible commands, the variable
'ansible_python_interpreter' should be set to the python interpreter
installed in 'virtualenv'. Note that this variable cannot be templated.

Change-Id: I0741923065246f9c5b168059fcd66504f2753c41
Related-Bug: #1731026
This commit is contained in:
Mark Goddard 2017-12-07 11:44:05 +00:00
parent 26536e2c1a
commit 69979efc2e
5 changed files with 139 additions and 0 deletions

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@ -39,3 +39,12 @@ redhat_pkg_removals:
- libvirt
- libvirt-daemon
- iscsi-initiator-utils
# Path to a virtualenv in which to install python packages. If None, a
# virtualenv will not be used.
virtualenv:
# Whether the virtualenv will inherit packages from the global site-packages
# directory. This is typically required for modules such as yum and apt which
# are not available on PyPI.
virtualenv_site_packages: True

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@ -56,17 +56,47 @@
with_items: "{{ redhat_pkg_install }}"
when: ansible_os_family == 'RedHat'
- name: Install virtualenv packages
package:
name: python-virtualenv
state: present
become: True
when: virtualenv is not none
- name: Install pip
easy_install:
name: pip
virtualenv: "{{ virtualenv is none | ternary(omit, virtualenv) }}"
virtualenv_site_packages: "{{ virtualenv is none | ternary(omit, virtualenv_site_packages) }}"
become: True
- name: Install latest pip in the virtualenv
pip:
name: pip
state: latest
virtualenv: "{{ virtualenv }}"
virtualenv_site_packages: "{{ virtualenv_site_packages }}"
become: True
when: virtualenv is not none
- name: Install docker SDK for python
pip:
name: docker
state: latest
virtualenv: "{{ virtualenv is none | ternary(omit, virtualenv) }}"
virtualenv_site_packages: "{{ virtualenv is none | ternary(omit, virtualenv_site_packages) }}"
become: True
- name: Ensure virtualenv has correct ownership
file:
path: "{{ virtualenv }}"
recurse: True
state: directory
owner: kolla
group: kolla
become: True
when: virtualenv is not none
- name: Remove packages
package:
name: "{{ item }}"

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@ -5,6 +5,7 @@ User Guides
:maxdepth: 1
quickstart
virtual-environments
multinode
multi-regions
operating-kolla

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@ -0,0 +1,76 @@
.. _virtual-environments:
====================
Virtual Environments
====================
Python `virtual environments <https://virtualenv.pypa.io/en/stable/>`_ provide
a mechanism for isolating python packages from the system site packages, and
other virtual environments. Kolla-ansible largely avoids this problem by
deploying services in Docker containers, however some python dependencies must
be installed both on the Ansible control host and the target hosts.
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:
.. code-block:: console
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.
.. code-block:: console
source /path/to/venv/bin/activate
(venv) pip install ansible
(venv) deactivate
To use the virtual environment, it should first be activated:
.. code-block:: console
source /path/to/venv/bin/activate
(venv) kolla-ansible --help
The virtual environment can be deactivated when necessary:
.. code-block:: console
(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:
.. code-block:: yaml
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``.

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@ -0,0 +1,23 @@
---
features:
- |
Adds support for installing python dependencies into a virtualenv on remote
hosts.
Installing python packages directly to the system site-packages can cause
various problems, in particular when pip overwrites a system package.
Python virtualenvs are one solution to this issue, as they allow python
packages to be installed in an isolated environment. 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.
The path to the virtualenv is configured via the ``virtualenv`` variable,
and access to site-packages is controlled via ``virtualenv_site_packages``.
The default value for ``virtualenv`` is None, in which case the old
behaviour of installing packages directly to the system site-packages is
maintained.
When executing other kolla-ansible commands, the variable
``ansible_python_interpreter`` should be set to the python interpreter
installed in ``virtualenv``. Note that this variable cannot be templated.