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

: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.
  - Implicit localhost does not appear in the ``hostvars`` magic variable unless demanded, such as by ``"{{ hostvars['localhost'] }}"``.
  - 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``.
Remove more docs build errors (#45364) * orphans testing pages to avoid not-in-toctree errors * orphans various pages pending reorg * adds module_utils and special_vars to main TOC * uses a glob for scenario_guide TOC * normalize and Sentence-case headings on community pages, typos * re-orgs community TOC, adds all pages to toctree * removes scenario guides index page * adds style guide to community index * basic update to style guide * fix typo that created a new error * removes not-in-toctree from ignore errors list * leave removing files for future cleanup task 2018-09-11 18:51:47 +02:00			`:orphan:`

draft implicit localhost docs (#31840) * draft implicit localhost docs * updated per feedback * corrected docs to follow desired behaviour * Edits 2017-11-23 01:13:56 +01:00			`.. _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.`
ansible/docs/docsite/rst/inventory/implicit_localhost.rst typo 2018-07-20 17:43:58 +02:00			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.
draft implicit localhost docs (#31840) * draft implicit localhost docs * updated per feedback * corrected docs to follow desired behaviour * Edits 2017-11-23 01:13:56 +01:00
			`.. note::`
			- This host is not targetable via any group, however it will use vars from ``host_vars`` and from the 'all' group.
Add implicit localhost hostvars note (#61956) 2019-09-16 20:00:29 +02:00			- Implicit localhost does not appear in the ``hostvars`` magic variable unless demanded, such as by ``"{{ hostvars['localhost'] }}"``.
Update implicit_localhost.rst (#45455) Adds a clarification about `inventory_dir/file` magic variables when using implicit localhost as per #45385 . +label: docsite_pr 2018-09-11 22:17:50 +02:00			- The ``inventory_file`` and ``inventory_dir`` magic variables are not available for the implicit localhost as they are dependent on each inventory host.
draft implicit localhost docs (#31840) * draft implicit localhost docs * updated per feedback * corrected docs to follow desired behaviour * Edits 2017-11-23 01:13:56 +01:00			- 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``.