Workshop Exercise - Writing Your First Playbook

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Table of Contents

• Workshop Exercise - Writing Your First Playbook
  • Objective
  • Guide
    • Step 1 - Playbook Basics
    • Step 2 - Creating Your Playbook
    • Step 3 - Running the Playbook
    • Step 4 - Checking the Playbook

Objective

In this exercise, you’ll use Ansible to conduct basic system setup tasks on a Red Hat Enterprise Linux server. You will become familiar with fundamental Ansible modules like dnf and user, and learn how to create and run playbooks.

Guide

Playbooks in Ansible are essentially scripts written in YAML format. They are used to define the tasks and configurations that Ansible will apply to your servers.

Step 1 - Playbook Basics

First, create a text file in YAML format for your playbook. Remember:

• Start with three dashes (---).
• Use spaces, not tabs, for indentation.

Key Concepts:

• hosts: Specifies the target servers or devices for your playbook to run against.
• tasks: The actions Ansible will perform.
• become: Allows privilege escalation (running tasks with elevated privileges).

NOTE: An Ansible playbook is designed to be idempotent, meaning if you run it multiple times on the same hosts, it ensures the desired state without making redundant changes.

Step 2 - Creating Your Playbook

Before creating your first playbook, ensure you are in the correct directory by changing to ~/lab_inventory:

cd ~/lab_inventory

Now create a playbook named system_setup.yml to perform basic system setup:

• Update all security related packages.
• Create a new user named ‘myuser’.

The basic structure looks as follows:

---
- name: Basic System Setup
  hosts: node1
  become: true
  tasks:
    - name: Update all security-related packages
      ansible.builtin.dnf:
        name: '*'
        state: latest
        security: true
   
    - name: Create a new user
      ansible.builtin.user:
        name: myuser
        state: present
        create_home: true

NOTE: Updating the packages may take a few minutes prior to the Ansible playbook completing.

• About the dnf module: This module is used for package management with DNF (Dandified YUM) on RHEL and other Fedora-based systems.

• About the user module: This module is used to manage user accounts.

Step 3 - Running the Playbook

Execute your playbook using the ansible-navigator command:

[student@ansible-1 lab_inventory]$ ansible-navigator run system_setup.yml -m stdout

Review the output to ensure each task is completed successfully.

Step 4 - Checking the Playbook

Now, let’s create a second playbook for post-configuration checks, named system_checks.yml:

---
- name: System Configuration Checks
  hosts: node1
  become: true
  tasks:
    - name: Check user existence
      ansible.builtin.command:
        cmd: id myuser
      register: user_check
 
    - name: Report user status
      ansible.builtin.debug:
        msg: "User 'myuser' exists."
      when: user_check.rc == 0

Run the checks playbook:

[student@ansible-1 lab_inventory]$ ansible-navigator run system_checks.yml -m stdout

Review the output to ensure the user creation was successful.

---

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