Inventory plugins allow users to point at data sources to compile the inventory of hosts that Ansible uses to target tasks, either via the ``-i /path/to/file`` and/or ``-i 'host1, host2'`` command line parameters or from other configuration sources.
In some circumstances, for example, if the inventory plugin does not use a YAML configuration file, you may need to enable the specific plugin. You can do this by setting ``enable_plugins`` in your :ref:`ansible.cfg <ansible_configuration_settings>` file in the ``[inventory]`` section. Modifying this will override the default list of enabled plugins. Here is the default list of enabled plugins that ships with Ansible:
To use an inventory plugin you need to provide an inventory source. Most of the time this is a file containing host information or a YAML configuration file with options for the plugin. You can use the ``-i`` flag to provide inventory sources or configure a default inventory path.
To start using an inventory plugin with a YAML configuration source, create a file with the accepted filename schema documented for the plugin in question, then add ``plugin: plugin_name``. Use the fully qualified name if the plugin is in a collection.
Each plugin should document any naming restrictions. In addition, the YAML config file must end with the extension ``yml`` or ``yaml`` to be enabled by default with the ``auto`` plugin (otherwise, see the section above on enabling plugins).
If you are using an inventory plugin in a playbook-adjacent collection and want to test your setup with ``ansible-inventory``, you will need to use the ``--playbook-dir`` flag.
Your inventory source might be a directory of inventory configuration files. The constructed inventory plugin only operates on those hosts already in inventory, so you may want the constructed inventory configuration parsed at a particular point (such as last). Ansible parses the directory recursively, alphabetically. You cannot configure the parsing approach, so name your files to make it work predictably. Inventory plugins that extend constructed features directly can work around that restriction by adding constructed options in addition to the inventory plugin options. Otherwise, you can use ``-i`` with multiple sources to impose a specific order, for example ``-i demo.aws_ec2.yml -i clouds.yml -i constructed.yml``.
You can create dynamic groups using host variables with the constructed ``keyed_groups`` option. The option ``groups`` can also be used to create groups and ``compose`` creates and modifies host variables. Here is an aws_ec2 example utilizing constructed features:
..code-block:: yaml
# demo.aws_ec2.yml
plugin: aws_ec2
regions:
- us-east-1
- us-east-2
keyed_groups:
# add hosts to tag_Name_value groups for each aws_ec2 host's tags.Name variable
- key: tags.Name
prefix: tag_Name_
separator: ""
groups:
# add hosts to the group development if any of the dictionary's keys or values is the word 'devel'
development: "'devel' in (tags|list)"
compose:
# set the ansible_host variable to connect with the private IP address without changing the hostname
If a host does not have the variables in the configuration above (in other words, ``tags.Name``, ``tags``, ``private_ip_address``), the host will not be added to groups other than those that the inventory plugin creates and the ``ansible_host`` host variable will not be modified.
Inventory plugins that support caching can use the general settings for the fact cache defined in the ``ansible.cfg`` file's ``[defaults]`` section or define inventory-specific settings in the ``[inventory]`` section. Individual plugins can define plugin-specific cache settings in their config file:
