Jinja2 templates

The copy module ships a static file as-is. The template module ships a file with Jinja2 placeholders inside, filled in per-host at deploy time — one template, many rendered outputs.

# templates/nginx.conf.j2
server {
    listen {{ nginx_port }};
    server_name {{ inventory_hostname }};

    location / {
        proxy_pass http://127.0.0.1:{{ app_port }};
    }

    {% if enable_ssl %}
    ssl_certificate     /etc/ssl/certs/{{ inventory_hostname }}.crt;
    ssl_certificate_key /etc/ssl/private/{{ inventory_hostname }}.key;
    {% endif %}
}

- name: Deploy nginx config from template
  template:
    src: templates/nginx.conf.j2
    dest: /etc/nginx/sites-available/app.conf
  vars:
    nginx_port: 80
    app_port: 3000
    enable_ssl: false
  notify: Restart nginx

{{ }} substitutes a value; {% %} runs logic — conditionals, loops — that doesn't itself appear in the output. Any variable in scope (inventory, group_vars, facts, playbook vars) is usable inside a template.