archive
/
ansible
mirror of https://github.com/ansible/ansible.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Update 'Ansible and BSD' section 'Setting the Python interpreter'. (#76825)

Browse Source
pull/76946/head
Vladimir Botka 3 years ago committed by GitHub
parent a1af1d94cd
commit 5448661aec
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 176 additions and 4 deletions
Show Stats Download Patch File Download Diff File

180
docs/docsite/rst/user_guide/intro_bsd.rst
Unescape Escape View File

@ -49,22 +49,194 @@ Once this is done you can now use other Ansible modules apart from the ``raw`` m
Setting the Python interpreter
------------------------------
To support a variety of Unix-like operating systems and distributions, Ansible cannot always rely on the existing environment or ``env`` variables to locate the correct Python binary. By default, modules point at ``/usr/bin/python`` as this is the most common location. On BSD variants, this path may differ, so it is advised to inform Ansible of the binary's location, through the ``ansible_python_interpreter`` inventory variable. For example:
To support a variety of Unix-like operating systems and distributions, Ansible cannot always rely on the existing environment or ``env`` variables to locate the correct Python binary. By default, modules point at ``/usr/bin/python`` as this is the most common location. On BSD variants, this path may differ, so it is advised to inform Ansible of the binary's location. See :ref:`INTERPRETER_PYTHON`. For example, set ``ansible_python_interpreter`` inventory variable:
.. code-block:: text
.. code-block:: ini
[freebsd:vars]
ansible_python_interpreter=/usr/local/bin/python
[openbsd:vars]
ansible_python_interpreter=/usr/local/bin/python3.8
If you use additional plugins beyond those bundled with Ansible, you can set similar variables for ``bash``, ``perl`` or ``ruby``, depending on how the plugin is written. For example:
FreeBSD packages and ports
""""""""""""""""""""""""""
In FreeBSD, there is no guarantee that either ``/usr/local/bin/python`` executable file or a link to an executable file is installed by default. The best practice for a remote host, with respect to Ansible, is to install at least the Python version supported by Ansible, for example, ``lang/python38``, and both meta ports ``lang/python3`` and ``lang/python``. Quoting from */usr/ports/lang/python3/pkg-descr*:
.. code-block:: text
This is a meta port to the Python 3.x interpreter and provides symbolic links
to bin/python3, bin/pydoc3, bin/idle3 and so on to allow compatibility with
minor version agnostic python scripts.
Quoting from */usr/ports/lang/python/pkg-descr*:
.. code-block:: text
This is a meta port to the Python interpreter and provides symbolic links
to bin/python, bin/pydoc, bin/idle and so on to allow compatibility with
version agnostic python scripts.
As a result, the following packages are installed:
.. code-block:: text
shell> pkg info | grep python
python-3.8_3,2 "meta-port" for the default version of Python interpreter
python3-3_3 Meta-port for the Python interpreter 3.x
python38-3.8.12_1 Interpreted object-oriented programming language
and the following executables and links
.. code-block:: text
shell> ll /usr/local/bin/ | grep python
lrwxr-xr-x 1 root wheel 7 Jan 24 08:30 python@ -> python3
lrwxr-xr-x 1 root wheel 14 Jan 24 08:30 python-config@ -> python3-config
lrwxr-xr-x 1 root wheel 9 Jan 24 08:29 python3@ -> python3.8
lrwxr-xr-x 1 root wheel 16 Jan 24 08:29 python3-config@ -> python3.8-config
-r-xr-xr-x 1 root wheel 5248 Jan 13 01:12 python3.8*
-r-xr-xr-x 1 root wheel 3153 Jan 13 01:12 python3.8-config*
INTERPRETER_PYTHON_FALLBACK
"""""""""""""""""""""""""""
Since version 2.8 Ansible provides a useful variable ``ansible_interpreter_python_fallback`` to specify a list of paths to search for Python. See :ref:`INTERPRETER_PYTHON_FALLBACK`. This list will be searched and the first item found will be used. For example, the configuration below would make the installation of the meta-ports in the previous section redundant, that is, if you don't install the Python meta ports the first two items in the list will be skipped and ``/usr/local/bin/python3.8`` will be discovered.
.. code-block:: ini
ansible_interpreter_python_fallback=['/usr/local/bin/python', '/usr/local/bin/python3', '/usr/local/bin/python3.8']
You can use this variable, prolonged by the lower versions of Python, and put it, for example, into the ``group_vars/all``. Then, override it for specific groups in ``group_vars/{group1, group2, ...}`` and for specific hosts in ``host_vars/{host1, host2, ...}`` if needed. See :ref:`ansible_variable_precedence`.
Debug the discovery of Python
"""""""""""""""""""""""""""""
For example, given the inventory
.. code-block:: ini
shell> cat hosts
[test]
test_11
test_12
test_13
[test:vars]
ansible_connection=ssh
ansible_user=admin
ansible_become=yes
ansible_become_user=root
ansible_become_method=sudo
ansible_interpreter_python_fallback=['/usr/local/bin/python', '/usr/local/bin/python3', '/usr/local/bin/python3.8']
ansible_perl_interpreter=/usr/local/bin/perl
The playbook below
.. code-block:: yaml+jinja
shell> cat playbook.yml
- hosts: test_11
gather_facts: false
tasks:
- command: which python
register: result
- debug:
var: result.stdout
- debug:
msg: |-
{% for i in _vars %}
{{ i }}:
{{ lookup('vars', i)|to_nice_yaml|indent(2) }}
{% endfor %}
vars:
_vars: "{{ query('varnames', '.*python.*') }}"
displays the details
.. code-block:: yaml
shell> ansible-playbook -i hosts playbook.yml
PLAY [test_11] *******************************************************************************
TASK [command] *******************************************************************************
[WARNING]: Platform freebsd on host test_11 is using the discovered Python interpreter at
/usr/local/bin/python, but future installation of another Python interpreter could change the
meaning of that path. See https://docs.ansible.com/ansible-
core/2.12/reference_appendices/interpreter_discovery.html for more information.
changed: [test_11]
TASK [debug] *********************************************************************************
ok: [test_11] =>
result.stdout: /usr/local/bin/python
TASK [debug] *********************************************************************************
ok: [test_11] =>
msg: |-
ansible_interpreter_python_fallback:
- /usr/local/bin/python
- /usr/local/bin/python3
- /usr/local/bin/python3.8
discovered_interpreter_python:
/usr/local/bin/python
ansible_playbook_python:
/usr/bin/python3
You can see that the first item from the list ``ansible_interpreter_python_fallback`` was discovered at the FreeBSD remote host. The variable ``ansible_playbook_python`` keeps the path to Python at the Linux controller that ran the playbook.
Regarding the warning, quoting from :ref:`INTERPRETER_PYTHON`
.. code-block:: text
The fallback behavior will issue a warning that the interpreter
should be set explicitly (since interpreters installed later may
change which one is used). This warning behavior can be disabled by
setting auto_silent or auto_legacy_silent. ...
You can either ignore it or get rid of it by setting the variable ``ansible_python_interpreter=auto_silent`` because this is, actually, what you want by using ``/usr/local/bin/python`` (*"interpreters installed later may change which one is used"*). For example
.. code-block:: ini
shell> cat hosts
[test]
test_11
test_12
test_13
[test:vars]
ansible_connection=ssh
ansible_user=admin
ansible_become=yes
ansible_become_user=root
ansible_become_method=sudo
ansible_interpreter_python_fallback=['/usr/local/bin/python', '/usr/local/bin/python3', '/usr/local/bin/python3.8']
ansible_python_interpreter=auto_silent
ansible_perl_interpreter=/usr/local/bin/perl
.. seealso::
* :ref:`interpreter_discovery`
* `FreeBSD Wiki: Ports/DEFAULT_VERSIONS <https://wiki.freebsd.org/Ports/DEFAULT_VERSIONS>`_
Additional variables
""""""""""""""""""""
If you use additional plugins beyond those bundled with Ansible, you can set similar variables for ``bash``, ``perl`` or ``ruby``, depending on how the plugin is written. For example:
.. code-block:: ini
[freebsd:vars]
ansible_python_interpreter=/usr/local/bin/python
ansible_perl_interpreter=/usr/bin/perl5
ansible_perl_interpreter=/usr/local/bin/perl
Which modules are available?

Write Preview
Loading…
Cancel
Save