Lab: Ansible basics - apply a configuration to multiple hosts

This lab sets up Ansible and applies a basic playbook to multiple hosts. By the end you will have the discipline for production Ansible use.

Tasks

Task 1: Install Ansible

sudo apt install ansible
ansible --version

Task 2: Build inventory

mkdir -p ~/ansible-lab
cd ~/ansible-lab

cat > inventory.ini <<EOF
[webservers]
localhost ansible_connection=local

[all:vars]
ansible_python_interpreter=/usr/bin/python3
EOF

Task 3: Test connectivity

ansible -i inventory.ini all -m ping

Task 4: Write a playbook

# site.yml
- name: Configure all hosts
  hosts: all
  become: yes
  tasks:
    - name: Ensure vim is installed
      apt:
        name: vim
        state: present
        update_cache: yes

    - name: Ensure /etc/motd has the right content
      copy:
        content: |
          Welcome to {{ ansible_hostname }}
          Managed by Ansible.
        dest: /etc/motd
        owner: root
        group: root
        mode: '0644'

Task 5: Apply

ansible-playbook -i inventory.ini site.yml

Task 6: Verify idempotency

ansible-playbook -i inventory.ini site.yml

Output should show changed=0.

Task 7: Check mode

ansible-playbook -i inventory.ini site.yml --check

Task 8: Document

ANSIBLE LAB
===========
Inventory: ~/ansible-lab/inventory.ini
Playbook: ~/ansible-lab/site.yml

Hosts managed: localhost (1)
Tasks applied:
- vim installed
- /etc/motd created

Idempotency: verified (re-run = changed=0)