Ansible Basics

Introduction

Ansible is an open-source automation tool that helps in configuration management, application deployment, task automation, and multi-node orchestration. It uses a simple language called YAML (Yet Another Markup Language) to describe automation tasks.

Key Concepts

• **Agentless**: Ansible does not require any agent to be installed on the target machines.
• **Idempotency**: Ansible ensures that the operations are idempotent, meaning running the same playbook multiple times won't change the system state if it's already in the desired state.
• **Modules**: Ansible comes with a wide range of built-in modules that can interact with the underlying operating system and other services.
• **Playbooks**: The files where Ansible code is written, defining the desired state of the system.

Installation

Ansible can be installed on various platforms. Below are the instructions for a few common environments:

On Ubuntu

sudo apt update
sudo apt install ansible

On CentOS

sudo yum install epel-release
sudo yum install ansible

On macOS

brew install ansible

Inventory Management

Inventory is a file where you define the hosts and groups of hosts that Ansible will manage. The default inventory file is located at /etc/ansible/hosts.

Example Inventory File

[webservers]
192.168.1.10
192.168.1.11

[databases]
192.168.1.20

Playbooks

Playbooks are the heart of Ansible's configuration management capabilities. They are written in YAML format.

Basic Playbook Example

- name: Install Apache
  hosts: webservers
  tasks:
    - name: Install httpd
      yum:
        name: httpd
        state: present
    - name: Start httpd service
      service:
        name: httpd
        state: started

Roles

Roles allow you to group related tasks and variables together. They enable better organization and reuse of your playbooks.

Creating a Simple Role

ansible-galaxy init myrole

This will create a directory structure for your role, which you can populate with tasks, handlers, and other files.

Best Practices

• Use version control for your playbooks.
• Organize playbooks and roles logically.
• Utilize Ansible Vault for sensitive data.
• Test playbooks in a staging environment before production.

FAQ