Writing Playbooks

Writing Playbooks

Playbook Structure

Basic Components

• Name and hosts
• Variables and facts
• Tasks and modules
• Handlers and notifications

Playbook Format

---
- name: Configure web servers
  hosts: webservers
  become: true
  vars:
    http_port: 80
    max_clients: 200

  tasks:
    - name: Install Apache
      yum:
        name: httpd
        state: present

    - name: Start Apache service
      service:
        name: httpd
        state: started
        enabled: true

Tasks and Modules

Task Structure

• Name (description)
• Module selection
• Module parameters
• Optional parameters

Common Modules

# Package management
- name: Install packages
  yum:
    name: [httpd, php, mysql]
    state: present

# Service management
- name: Manage service
  service:
    name: httpd
    state: started

# File operations
- name: Copy configuration
  copy:
    src: files/httpd.conf
    dest: /etc/httpd/conf/httpd.conf

Handlers and Notifications

Handler Definition

handlers:
  - name: restart apache
    service:
      name: httpd
      state: restarted

  - name: reload apache
    service:
      name: httpd
      state: reloaded

Notifying Handlers

tasks:
  - name: Update Apache configuration
    copy:
      src: files/httpd.conf
      dest: /etc/httpd/conf/httpd.conf
    notify: restart apache

Task Control

Conditionals

tasks:
  - name: Install Apache (RedHat)
    yum:
      name: httpd
      state: present
    when: ansible_os_family == "RedHat"

  - name: Install Apache (Debian)
    apt:
      name: apache2
      state: present
    when: ansible_os_family == "Debian"

Loops

tasks:
  - name: Create users
    user:
      name: ""
      state: present
    loop:
      - john
      - jane
      - bob

Error Handling

Ignore Errors

tasks:
  - name: Run potentially failing command
    command: /bin/false
    ignore_errors: true

Block Error Handling

blocks:
  - block:
      - name: Run risky task
        command: /bin/risky_command
    rescue:
      - name: Run recovery task
        command: /bin/recovery_command
    always:
      - name: Always run this task
        command: /bin/cleanup_command

Best Practices

Organization

• Use meaningful names
• Group related tasks
• Keep playbooks focused
• Use roles for reusability

Documentation

• Add comments
• Use descriptive names
• Include usage examples
• Document variables

Version Control

• Use Git for playbooks
• Follow branching strategy
• Review changes
• Test before merging

Practical Exercise

Creating a Web Server Playbook

1. Define inventory
2. Write basic tasks
3. Add handlers
4. Test and verify

Debugging Tips

• Use --check mode
• Enable verbose output
• Check syntax
• Use debug module

Key Takeaways

• Structure matters
• Use handlers effectively
• Implement error handling
• Follow best practices

Additional Resources

• Ansible Playbook Documentation
• Best Practices Guide
• Module Index