More Key features on Ansible

 More Ansible Key concepts.

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Above: More Difference between tasks and handlers in ansible playbooks.

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Above:  Custom Ansible Modules in Ansible.

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Structure of an Ansible Playbook

An Ansible Playbook is structured in YAML and consists of one or more plays, which define a set of tasks to be executed on specified hosts. Here’s the typical structure of an Ansible Playbook:

Basic Structure of an Ansible Playbook

# yaml

---
- name: Example Playbook
  hosts: webservers
  become: true  # Run tasks with elevated privileges (sudo)
  
  vars:
    package_name: nginx

  tasks:
    - name: Install a package
      apt:
        name: "{{ package_name }}"
        state: present
      when: ansible_os_family == "Debian"

    - name: Ensure the service is running
      service:
        name: "{{ package_name }}"
        state: started
        enabled: true

  handlers:
    - name: Restart nginx
      service:
        name: nginx
        state: restarted

 

Key Components of an Ansible Playbook

1. --- (YAML Header)

• Indicates that the file is in YAML format.

2. - name: (Play Definition)

• Defines a play, which includes target hosts, roles, and tasks.

3. hosts:

• Specifies the group of machines (from inventory) where the playbook will run.

4. become:

• Grants administrative privileges (sudo) when necessary.

5. vars: (Variables)

• Allows defining reusable variables.

6. tasks: (List of Tasks)

• Contains a list of actions to execute on the target machines.
• Each task has:
  • name: (Descriptive name)
  • Module (e.g., apt, service)
  • Arguments (e.g., name: nginx, state: present)

7. when: (Conditional Execution)

• Executes a task only if a condition is met.

8. handlers: (Event-Driven Actions)

• Triggered by tasks (e.g., restart a service after package installation).

Advanced Playbook Structure

A more structured playbook with multiple plays and roles:

# yaml

---
- name: Setup Web Servers
  hosts: webservers
  become: true
  roles:
    - webserver

- name: Setup Database Servers
  hosts: dbservers
  become: true
  roles:
    - database

Here, roles organize tasks into reusable components.

Ansible Playbook Best Practices

 Use roles for modularity (ansible-galaxy init <role-name>)
Leverage variables (vars, vars_files, group_vars) for flexibility
Use handlers to restart services only when needed
Utilize when: to conditionally execute tasks
Keep playbooks DRY (Don’t Repeat Yourself) with includes & roles.