Lookups

Lookup plugins allow access to outside data sources. Like all templating, these plugins are evaluated on the Ansible control machine, and can include reading the filesystem as well as contacting external datastores and services. This data is then made available using the standard templating system in Ansible.

Note

  • Lookups occur on the local computer, not on the remote computer.
  • They are executed within the directory containing the role or play, as opposed to local tasks which are executed with the directory of the executed script.
  • You can pass wantlist=True to lookups to use in jinja2 template “for” loops.
  • Lookups are an advanced feature. You should have a good working knowledge of Ansible plays before incorporating them.

Warning

Some lookups pass arguments to a shell. When using variables from a remote/untrusted source, use the |quote filter to ensure safe usage.

Lookups and loops

lookup plugins are a way to query external data sources, such as shell commands or even key value stores.

Before Ansible 2.5, lookups were mostly used indirectly in with_<lookup> constructs for looping. Starting with Ansible version 2.5, lookups are used more explicitly as part of Jinja2 expressions fed into the loop keyword.

Lookups and variables

One way of using lookups is to populate variables. These macros are evaluated each time they are used in a task (or template):

vars:
  motd_value: "{{ lookup('file', '/etc/motd') }}"
tasks:
  - debug:
      msg: "motd value is {{ motd_value }}"

For more details and a complete list of lookup plugins available, please see Working With Plugins.

See also

Working With Playbooks
An introduction to playbooks
Conditionals
Conditional statements in playbooks
Using Variables
All about variables
Loops
Looping in playbooks
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© 2012–2018 Michael DeHaan
© 2018–2019 Red Hat, Inc.
Licensed under the GNU General Public License version 3.
https://docs.ansible.com/ansible/2.8/user_guide/playbooks_lookups.html