What Are Variables in Ansible?

Variables in Ansible are named values that store data for use in your automation tasks. You can think of a variable as a label that holds information, such as a server name, a configuration setting, or a file path. Variables allow you to reuse values, keep your playbooks organized, and avoid hardcoding information directly into your automation scripts.

Why Use Variables?

Using variables in your playbooks provides several key benefits:

• Make your playbooks reusable for different environments, such as development, staging, or production;
• Avoid repetition by defining a value once and using it in multiple places;
• Simplify updates by changing a variable's value in one location instead of searching through your playbook;
• Increase clarity by giving descriptive names to important values.

Making Playbooks Dynamic

Variables help make your playbooks dynamic and flexible. Instead of writing separate playbooks for each server or environment, you can use variables to customize behavior. For example, you might use a variable to specify the version of a package to install, the user account to create, or the directory path for a deployment. This approach saves time and reduces errors, especially as your automation grows.

By understanding and using variables, you unlock the full power of Ansible to manage systems efficiently and adapt to changing requirements.

Ways to Define Variables in Ansible

Ansible provides several flexible methods for defining variables. Understanding where and how to set variables helps you organize your automation and control how values are applied.

Defining Variables in Playbooks

You can define variables directly inside your playbooks using the vars section. These variables are available only within the playbook where they are set.

- name: Install Apache
  hosts: webservers
  vars:
    http_port: 80
  tasks:
    - name: Ensure Apache is installed
      yum:
        name: httpd
        state: present

• Use the vars section to set variables for specific plays;
• Variables in playbooks are easy to read and maintain when used for small sets of values;
• These variables override values set in inventory files or variable files.

Defining Variables in Inventory Files

You can assign variables to hosts or groups directly in your inventory file. This method is useful for setting values based on host or group context.

Example of an INI-style inventory file:

[webservers]
server1 ansible_host=192.168.1.10 http_port=8080
server2 ansible_host=192.168.1.11 http_port=8081

• Attach variables to specific hosts or groups;
• Useful for environment-specific settings like IP addresses or ports;
• Inventory variables are overridden by playbook variables if both are set.

Defining Variables in Variable Files

You can organize variables in separate YAML files and load them into your playbooks. This approach is helpful for managing large sets of variables or sharing values across multiple playbooks.

Example of a variable file (vars.yml):

http_port: 8080
max_clients: 200

Including the variable file in your playbook:

- name: Configure web server
  hosts: webservers
  vars_files:
    - vars.yml
  tasks:
    - name: Start web server
      service:
        name: httpd
        state: started

• Store variables in separate files for better organization;
• Reuse variable files across multiple playbooks;
• Variable files can be encrypted for sensitive data using Ansible Vault.

Using these methods, you can control where variables are defined and how they are applied during automation. This flexibility allows you to write clear, reusable, and maintainable Ansible playbooks.

---
- name: Print a message using a variable
  hosts: localhost
  vars:
    greeting: "Hello, Ansible!"
  tasks:
    - name: Show greeting message
      debug:
        msg: "The message is: {{ greeting }}"