# Jinja2 Templates — Ansible: Automate Servers with Playbooks

Source: https://www.geekswithgeeks.com/en/ansible/var-templates

> Generate configuration files from templates using variables, defaults and loops.

## One template, many files

The **`template`** module renders a **Jinja2** file for each host and copies the result. Inside templates, `{{ var }}` prints a value, `{{ var | default(80) }}` supplies a fallback with a **filter**, and `{% for %}` loops. Use templates for configs that differ per host or environment, and keep static files in `files/` for the `copy` module. A header comment such as "managed by Ansible" warns people not to edit the file by hand.

## The template

`http_port` comes from the `[web:vars]` group in the inventory, `users` from the play's vars.

```jinja
# managed by Ansible - do not edit
server_name={{ inventory_hostname }}
port={{ http_port | default(80) }}
{% for u in users %}
user={{ u }}
{% endfor %}
```

## The rendered file, run

This is the real `out/web1.conf` produced by the first run: the hostname, the port 8080 from the group variable, and one line per user.

```ini
# managed by Ansible - do not edit
server_name=web1
port=8080
user=asha
user=ravi
```

**Quiz:** What does `{{ http_port | default(80) }}` do?

- [ ] Raises an error if defined
- [ ] Always prints 80
- [ ] Deletes http_port
- [x] Uses http_port if defined, otherwise 80

*Answer:* Uses http_port if defined, otherwise 80. The default filter provides a fallback only when the variable is undefined.