ansible/docs/docsite/rst/reference_appendices/interpreter_discovery.rst
Matt Davis 4d3a6123d5
Python interpreter discovery (#50163)
* Python interpreter discovery

* No longer blindly default to only `/usr/bin/python`
* `ansible_python_interpreter` defaults to `auto_legacy`, which will discover the platform Python interpreter on some platforms (but still favor `/usr/bin/python` if present for backward compatibility). Use `auto` to always use the discovered interpreter, append `_silent` to either value to suppress warnings.
* includes new doc utility method `get_versioned_doclink` to generate a major.minor versioned doclink against docs.ansible.com (or some other config-overridden URL)

* docs revisions for python interpreter discovery

(cherry picked from commit 5b53c0012ab7212304c28fdd24cb33fd8ff755c2)

* verify output on some distros, cleanup
2019-02-27 23:52:02 -08:00

51 lines
2.5 KiB
ReStructuredText

.. _interpreter_discovery:
Interpreter Discovery
=====================
Most Ansible modules that execute under a POSIX environment require a Python
interpreter on the target host. Unless configured otherwise, Ansible will
attempt to discover a suitable Python interpreter on each target host
the first time a Python module is executed for that host.
To control the discovery behavior:
* for individual hosts and groups, use the ``ansible_python_interpreter`` inventory variable
* globally, use the ``interpreter_python`` key in the ``[defaults]`` section of ``ansible.cfg``
Use one of the following values:
auto_legacy : (default in 2.8)
Detects the target OS platform, distribution, and version, then consults a
table listing the correct Python interpreter and path for each
platform/distribution/version. If an entry is found, and ``/usr/bin/python`` is absent, uses the discovered interpreter (and path). If an entry
is found, and ``/usr/bin/python`` is present, uses ``/usr/bin/python``
and issues a warning.
This exception provides temporary compatibility with previous versions of
Ansible that always defaulted to ``/usr/bin/python``, so if you have
installed Python and other dependencies at ``usr/bin/python`` on some hosts,
Ansible will find and use them with this setting.
If no entry is found, or the listed Python is not present on the
target host, searches a list of common Python interpreter
paths and uses the first one found; also issues a warning that future
installation of another Python interpreter could alter the one chosen.
auto : (future default in 2.12)
Detects the target OS platform, distribution, and version, then consults a
table listing the correct Python interpreter and path for each
platform/distribution/version. If an entry is found, uses the discovered
interpreter.
If no entry is found, or the listed Python is not present on the
target host, searches a list of common Python interpreter
paths and uses the first one found; also issues a warning that future
installation of another Python interpreter could alter the one chosen.
auto_legacy_silent
Same as ``auto_legacy``, but does not issue warnings.
auto_silent
Same as ``auto``, but does not issue warnings.
You can still set ``ansible_python_interpreter`` to a specific path at any
variable level (for example, in host_vars, in vars files, in playbooks, etc.).
Setting a specific path completely disables automatic interpreter discovery; Ansible always uses the path specified.