ansible/docs/docsite/rst/inventory/implicit_localhost.rst

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[WIP] Backport/2.7/batch port (#45859) Batch of docs backports: * docs: Clarify include_task v import_tasks with conditionals (#43856) (cherry picked from commit 6be42a2a0ec6afb1e8a2f5f48bef4e9c1588dd34) * Add single quotes around package name (#45152) (cherry picked from commit 0d81386144298af42810fbf4d88668c67425d29c) * prefer ansible_facts namespace and dict notation (#44980) (cherry picked from commit 44510448b07c16bbf7767076e2392f47dcb7e824) * fix cherrypick conflict - scenario_guides * Update implicit_localhost.rst (#45455) (cherry picked from commit f68cd1acc65fe7914f4adda7eb3b6f2b1a78ef1e) * updated fbsd install instructions (#45309) (cherry picked from commit e9c2695ce745cf42d1c69166d838ad17555d8b99) * Change "Defaulting Undefined Variables" (#41379) (cherry picked from commit e35c4be1c1a5e40d1b5e2b33ac04e83e4a5fc4e7) * adds license details to dev guide pages (#45574) (cherry picked from commit 6e68d77f6dde19f5eb5c77e5f0829958597c2333) * FAQ: fix a typo, add link to 'vars' lookup (#42412) (cherry picked from commit 95649dc793e178b9b9d796865db0a1ce2c2c2355) * Fix link and toctree (#45595) (cherry picked from commit 6999bf318f7c786abdabdfa9c129a5151172cd61) * Improve the local toctree (and title) (#45590) (cherry picked from commit afea00fa9fe3e5a04b17e4016e61b9399d4a1a50) * Add undocumented configuration parameter and explain in porting guide (#36059) (cherry picked from commit a892a6ef03a0b4e0e6fc7b66c20f82154cad8a8d) * Simplify PPA installation for Ubuntu (#45690) (cherry picked from commit 78e9f452a5bb9d2c8b1d1ae9bdaa3bd86e1b972b) * adding git+ssh uri scheme (#36025) (cherry picked from commit 84a42577740b14d77e9571dfd242261b91283d94) * Add workaround for non-standard kerberos environments (#41465) (cherry picked from commit 4e532e0ad99396cbfc5dd32a0b02efcc57523b99) * Restore license agreement (#45809) (cherry picked from commit f430f60541899792356efd3ba7f31f7324731f10) * partial cherry-pick - lenovo doc update PR 45483
2018-09-20 03:02:01 +00:00
:orphan:
.. _implicit_localhost:
Implicit 'localhost'
====================
When you try to reference a ``localhost`` and you don't have it defined in inventory, Ansible will create an implicit one for you.::
- hosts: all
tasks:
- name: check that i have log file for all hosts on my local machine
stat: path=/var/log/hosts/{{inventory_hostname}}.log
delegate_to: localhost
In a case like this (or ``local_action``) when Ansible needs to contact a 'localhost' but you did not supply one, we create one for you. This host is defined with specific connection variables equivalent to this in an inventory::
...
hosts:
localhost:
vars:
ansible_connection: local
ansible_python_interpreter: "{{ansible_playbook_python}}"
This ensures that the proper connection and Python are used to execute your tasks locally.
You can override the built-in implicit version by creating a ``localhost`` host entry in your inventory. At that point, all implicit behaviors are ignored; the ``localhost`` in inventory is treated just like any other host. Group and host vars will apply, including connection vars, which includes the ``ansible_python_interpreter`` setting. This will also affect ``delegate_to: localhost`` and ``local_action``, the latter being an alias to the former.
.. note::
- This host is not targetable via any group, however it will use vars from ``host_vars`` and from the 'all' group.
[WIP] Backport/2.7/batch port (#45859) Batch of docs backports: * docs: Clarify include_task v import_tasks with conditionals (#43856) (cherry picked from commit 6be42a2a0ec6afb1e8a2f5f48bef4e9c1588dd34) * Add single quotes around package name (#45152) (cherry picked from commit 0d81386144298af42810fbf4d88668c67425d29c) * prefer ansible_facts namespace and dict notation (#44980) (cherry picked from commit 44510448b07c16bbf7767076e2392f47dcb7e824) * fix cherrypick conflict - scenario_guides * Update implicit_localhost.rst (#45455) (cherry picked from commit f68cd1acc65fe7914f4adda7eb3b6f2b1a78ef1e) * updated fbsd install instructions (#45309) (cherry picked from commit e9c2695ce745cf42d1c69166d838ad17555d8b99) * Change "Defaulting Undefined Variables" (#41379) (cherry picked from commit e35c4be1c1a5e40d1b5e2b33ac04e83e4a5fc4e7) * adds license details to dev guide pages (#45574) (cherry picked from commit 6e68d77f6dde19f5eb5c77e5f0829958597c2333) * FAQ: fix a typo, add link to 'vars' lookup (#42412) (cherry picked from commit 95649dc793e178b9b9d796865db0a1ce2c2c2355) * Fix link and toctree (#45595) (cherry picked from commit 6999bf318f7c786abdabdfa9c129a5151172cd61) * Improve the local toctree (and title) (#45590) (cherry picked from commit afea00fa9fe3e5a04b17e4016e61b9399d4a1a50) * Add undocumented configuration parameter and explain in porting guide (#36059) (cherry picked from commit a892a6ef03a0b4e0e6fc7b66c20f82154cad8a8d) * Simplify PPA installation for Ubuntu (#45690) (cherry picked from commit 78e9f452a5bb9d2c8b1d1ae9bdaa3bd86e1b972b) * adding git+ssh uri scheme (#36025) (cherry picked from commit 84a42577740b14d77e9571dfd242261b91283d94) * Add workaround for non-standard kerberos environments (#41465) (cherry picked from commit 4e532e0ad99396cbfc5dd32a0b02efcc57523b99) * Restore license agreement (#45809) (cherry picked from commit f430f60541899792356efd3ba7f31f7324731f10) * partial cherry-pick - lenovo doc update PR 45483
2018-09-20 03:02:01 +00:00
- The ``inventory_file`` and ``inventory_dir`` magic variables are not available for the implicit localhost as they are dependent on **each inventory host**.
- This implicit host also gets triggered by using ``127.0.0.1`` or ``::1`` as they are the IPv4 and IPv6 representations of 'localhost'.
- Even though there are many ways to create it, there will only ever be ONE implicit localhost, using the name first used to create it.
- Having ``connection: local`` does NOT trigger an implicit localhost, you are just changing the connection for the ``inventory_hostname``.