[Ansible] – Using the module template and jinja files to update hosts

The module template is helpful to create contents in the hosts. Jinja allows work by creating dynamically contents as the follows examples.

Variables Definitions

{{ ansible_user_dir }}    {{ ansible_user_id }}

NOTE: The above example is using the facts variables which can be obtained by the command “ansible <host> -m setup”. For further information check the Ansible facts post.

Loops

{% for item in books %}
  {{ item }}
{% endfor %}

{% for mybook in books if not mybook == "ansible in action"%}
  {{ loop.index }} - {{ mybook }}
{% endfor %}

Conditionals

{% if ok %}
    {{ result }}
{% endif %}

 Changing the output format

{{ output | to_json }} # To print output in the json format {{ output | to_yaml }} # To print output in the yaml format

{{ output | to_nice_json }} #To print pretty in the json format {{ output | to_nice_yaml }} #To print pretty in the yam format

{{ output | from_json }} # To parse from json {{ output | from_yaml }} # To parse from yamls

Example of Usage

Following an example over how it can be used.

$cat users.j2 

The Ansible user {{ ansible_user_dir }} has the ID {{ansible_user_id }}.

Then, the above jinja file can be used with the module templates to add a file with this content in all hosts defined in the inventory as defined in the following playbook which is an example.

---
- hosts: all
  tasks:
    - template:
        src: users.j2
        dest: /tmp/user
        owner: root
        group: root
        mode: 0755

So, if the above playbook is executed then all hosts will have a file created by the Jinja template file in the path /tmp/user. The file will be created with the owner root and will have the permission 0755 as described on it.

For further information see the following references.

• template – Templates a file out to a remote server
• Using Variables: About Jinja2
• Jinja Templates docs