Install

pip install ansible

Inventory

# hosts.ini
[webservers]
server1 ansible_host=1.2.3.4
server2 ansible_host=5.6.7.8

Playbook

---
- hosts: webservers
  become: yes
  tasks:
    - name: Update packages
      apt: update_cache=yes upgrade=yes
    - name: Install nginx
      apt: name=nginx state=latest
ansible-playbook -i hosts.ini playbook.yml