constructed¶

Collection Note

This module is part of the ansible.builtin collection. To install the collection, use:

ansible-galaxy collection install ansible.builtin

Added in version 2.4.

Synopsis¶

Uses a YAML configuration file with a valid YAML or C(.config) extension to define var expressions and group conditionals
The Jinja2 conditionals that qualify a host for membership.
The Jinja2 expressions are calculated and assigned to the variables
Only variables already available from previous inventories or the fact cache can be used for templating.
When O(strict) is False, failed expressions will be ignored (assumes vars were missing).

Parameters¶

Parameter	Defaults / Choices	Comments
compose dict		Create vars from jinja2 expressions.
groups dict		Add hosts to group based on Jinja2 conditionals.
keyed_groups list / elements=dict		Add hosts to group based on the values of a variable.
keyed_groups.default_value		The default value when the host variable's value is an empty string. This option is mutually exclusive with O(keyed_groups[].trailing_separator).
keyed_groups.key		The key from input dictionary used to generate groups.
keyed_groups.parent_group		parent group for keyed group.
keyed_groups.prefix		A keyed group name will start with this prefix.
keyed_groups.separator	Default: _	separator used to build the keyed group name.
keyed_groups.trailing_separator	Default: True	Set this option to V(false) to omit the O(keyed_groups[].separator) after the host variable when the value is an empty string. This option is mutually exclusive with O(keyed_groups[].default_value).
leading_separator boolean	Default: True	Use in conjunction with O(keyed_groups). By default, a keyed group that does not have a prefix or a separator provided will have a name that starts with an underscore. This is because the default prefix is V("") and the default separator is V("_"). Set this option to V(false) to omit the leading underscore (or other separator) if no prefix is given. If the group name is derived from a mapping the separator is still used to concatenate the items. To not use a separator in the group name at all, set the separator for the keyed group to an empty string instead. Version Added: 2.11
plugin required	Choices: ansible.builtin.constructed, constructed	token that ensures this is a source file for the 'constructed' plugin.
strict bool		If V(yes) make invalid entries a fatal error, otherwise skip and continue. Since it is possible to use facts in the expressions they might not always be available and we ignore those errors by default.
use_extra_vars bool		Merge extra vars into the available variables for composition (highest precedence). Env: ANSIBLE_INVENTORY_USE_EXTRA_VARS Version Added: 2.11
use_vars_plugins boolean		Normally, for performance reasons, vars plugins get executed after the inventory sources complete the base inventory, this option allows for getting vars related to hosts/groups from those plugins. The host_group_vars (enabled by default) 'vars plugin' is the one responsible for reading host_vars/ and group_vars/ directories. This will execute all vars plugins, even those that are not supposed to execute at the 'inventory' stage. See vars plugins docs for details on 'stage'. Implicit groups, such as 'all' or 'ungrouped', need to be explicitly defined in any previous inventory to apply the corresponding group_vars Version Added: 2.11

Examples¶

    # inventory.config file in YAML format
    plugin: ansible.builtin.constructed
    strict: False
    compose:
        var_sum: var1 + var2

        # this variable will only be set if I have a persistent fact cache enabled (and have non expired facts)
        # `strict: False` will skip this instead of producing an error if it is missing facts.
        server_type: "ansible_hostname | regex_replace ('(.{6})(.{2}).*', '\\2')"
    groups:
        # simple name matching
        webservers: inventory_hostname.startswith('web')

        # using ec2 'tags' (assumes aws inventory)
        development: "'devel' in (ec2_tags|list)"

        # using other host properties populated in inventory
        private_only: not (public_dns_name is defined or ip_address is defined)

        # complex group membership
        multi_group: (group_names | intersect(['alpha', 'beta', 'omega'])) | length >= 2

    keyed_groups:
        # this creates a group per distro (distro_CentOS, distro_Debian) and assigns the hosts that have matching values to it,
        # using the default separator "_"
        - prefix: distro
          key: ansible_distribution

        # the following examples assume the first inventory is from the `aws_ec2` plugin
        # this creates a group per ec2 architecture and assign hosts to the matching ones (arch_x86_64, arch_sparc, etc)
        - prefix: arch
          key: architecture

        # this creates a group per ec2 region like "us_west_1"
        - prefix: ""
          separator: ""
          key: placement.region

        # this creates a common parent group for all ec2 availability zones
        - key: placement.availability_zone
          parent_group: all_ec2_zones