A playbook is a YAML file mapping plays (host groups) to tasks (module calls). Tasks run top to bottom. Supporting pieces:

• Variables — parameterize plays; templates (Jinja2) render config files
• Handlers — tasks that run only when notified by a change (e.g. restart a service after its config changes)
• Roles — a standard directory structure (tasks/, templates/, vars/, handlers/) that packages reusable automation, shareable via Ansible Galaxy

Roles are the unit of reuse and organization for anything non-trivial.

- name: Configure web servers
  hosts: webservers
  become: true
  tasks:
    - name: Install nginx
      ansible.builtin.apt:
        name: nginx
        state: present

    - name: Deploy site config
      ansible.builtin.template:
        src: nginx.conf.j2
        dest: /etc/nginx/nginx.conf
      notify: Restart nginx

  handlers:
    - name: Restart nginx
      ansible.builtin.service:
        name: nginx
        state: restarted

1. Write a play that installs a package and deploys a templated config file.
2. Add a handler that restarts a service only when its config changes.
3. Explain the standard directory structure of a role.
4. Describe how Ansible Galaxy helps reuse community roles.

• ↗ Ansible — Playbooks