ansible – Introduction to playbooks – Overview

In Ansible, a playbook is is a YAML file containing the definition of how a server should look. In a playbook you define what actions Ansible should take to get the server in the state you want. Only what you define gets done.

This is a basic Ansible playbook that installs git on every host belonging to the web group:

---
- name: Git installation
  hosts: web
  remote_user: root
  tasks: 
    - name: Install Git
      apt: name=git state=present

if you want to reproduce, please indicate the source:
ansible – Introduction to playbooks – Overview - CodeDay