An Ansible playbook is a configuration management file written in YAML format that defines a series of tasks to be executed on one or more target systems. It provides a structured and reusable way to automate IT workflows.

Key components of an Ansible playbook:

• Hosts: Defines the target systems or groups of systems.

• Tasks: Specifies the actions to be performed on the target systems.

• Variables: Stores data that can be used throughout the playbook.

• Templates: Creates files dynamically based on templates and variables.

• Handlers: Defines actions to be triggered based on specific conditions.

Example playbook:

YAML

---  
- name: Install Apache web server    hosts: webservers    
tasks:      
  - name: Ensure Apache installed        
    apt: name=apache2 state=present      
  - name: Start Apache service             service: name=apache2 state=started

Explanation:

• Hosts: Specifies the group of hosts named "webservers".

• Tasks: Defines two tasks:

  • Installs the Apache web server package using the apt module.

  • Starts the Apache service using the service module.

Key benefits of using Ansible playbooks:

• Automation: Automates repetitive tasks, saving time and effort.

• Consistency: Ensures that systems are configured consistently across different environments.

• Idempotency: Guarantees that changes are applied only once, even if a playbook is run multiple times.

• Reusability: Playbooks can be reused and shared across different projects.

• Version control: Playbooks can be version-controlled, making it easy to track changes and revert to previous states.

Additional features of Ansible playbooks:

• Roles: Modularize playbooks by organizing tasks and variables into reusable units.

• Includes: Include other playbooks or roles within a main playbook.

• Loops: Iterate over lists of items and perform tasks on each item.

• Conditionals: Execute tasks based on specific conditions.

• Callbacks: Trigger custom actions based on events.