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Ansible - Day 1 (Write your first playbook)

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Sandeep Naidu
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Table of contents

Ansible - Day 1 (Write your first playbook)

Table of contents

Ansible Basics - Getting Started

What is Ansible?

Ansible is a powerful open-source automation tool that can help you manage and configure your servers, applications, and infrastructure effortlessly. Whether you're a seasoned pro or a beginner in the world of DevOps, Ansible is here to simplify your life.

Why Use Ansible?

  • Simplicity: Ansible uses plain English and YAML files for configuration, making it accessible to everyone.

  • Agentless: You don't need to install agents on target servers. Ansible works over SSH or WinRM, which most systems support by default.

  • Versatility: It can handle a wide range of tasks, from simple server configuration to complex application deployments.

Introduction to Ansible

Ansible Components

  • Control Node: This is your Ansible machine, where you write your playbooks and manage everything from.

  • Managed Nodes: These are the servers or devices you want to automate. Ansible communicates with them via SSH (Linux) or WinRM (Windows).

  • Playbooks: Think of them as recipes. Playbooks define the tasks you want to perform on your managed nodes.

  • Modules: These are Ansible's building blocks. Modules are used to execute tasks, such as installing software or creating files.

Setting Up Your Environment

Step 1: Install Ansible

On your control node (your laptop or a dedicated server):

sudo apt-get install ansible  # For Ubuntu

Step 2: Inventory File

Create an inventory file (e.g., inventory) where you list the IP addresses or hostnames of your managed nodes:

[web]
192.168.1.10
[database]
192.168.1.11

Step 3: SSH Key

Make sure you have SSH access to your managed nodes. If not, generate an SSH key on your control node and copy the public key to your managed nodes.

ssh-keygen  # Generate SSH key
ssh-copy-id <username>@<managed_node_ip>  # Copy your SSH key to the managed node

Step 4: Test the Connection

You can test the connection to your managed nodes using the following command:

ansible -m ping -i inventory all

Writing Your First Playbook

Now, it's time to put Ansible to work. Create your first playbook (e.g., first_playbook.yml) using a text editor:

---
- name: Install Nginx
  hosts: web
  become: yes  # Run tasks with sudo
  tasks:
    - name: Update apt cache
      apt:
        update_cache: yes

    - name: Install Nginx
      apt:
        name: nginx
        state: present

    - name: Start Nginx
      service:
        name: nginx
        state: started

In this simple playbook, we:

  1. Update the package cache.

  2. Install Nginx.

  3. Start the Nginx service.

To run your playbook, use the following command:

ansible-playbook -i inventory my_first_playbook.yml

Ansible will take care of installing Nginx on your web server.

That's it for our introduction to Ansible! We've covered the basics, set up your environment, and written your first playbook.

Stay tuned for more Ansible topics and examples.

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