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Aisalkyn Aidarova
Aisalkyn Aidarova

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What is Ansible?

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Ansible is an open-source automation tool used for:

  • Configuration management
  • Application deployment
  • Infrastructure provisioning
  • Orchestration

It helps DevOps engineers automate tasks on multiple servers at the same time.

Who created it?

  • Originally created by Michael DeHaan
  • Now owned and maintained by Red Hat

How Ansible Works (Simple)

Ansible uses:

  • Control Node → your machine (where Ansible runs)
  • Managed Nodes → remote servers
  • SSH → to connect (no agent needed)

Unlike many tools, Ansible is agentless — you don’t install anything on target servers.

Core Components

1. Inventory

List of servers:

[web]
192.168.1.10
192.168.1.11
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2. Playbook (YAML file)

Automation instructions written in YAML:

- hosts: web
  become: yes
  tasks:
    - name: Install nginx
      apt:
        name: nginx
        state: present
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3. Modules

Prebuilt functions (like plugins):

  • apt
  • yum
  • copy
  • file
  • service
  • user

Why DevOps Engineers Use Ansible

Since you teach DevOps and work heavily with AWS:

You can use Ansible to:

  • Configure EC2 instances
  • Install Docker automatically
  • Deploy applications
  • Configure Nginx
  • Manage users
  • Set up Kubernetes nodes
  • Patch servers

Example:

ansible all -m ping
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Tests connection to all servers.

Where Ansible Fits in DevOps

Tool Purpose
Terraform Create infrastructure
Ansible Configure servers
Docker Containerize apps
Kubernetes Orchestrate containers

Simple Real-World Example

Instead of logging into 20 EC2 servers and running:

sudo apt update
sudo apt install docker -y
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You run one playbook, and Ansible does it everywhere automatically.

Ansible is a configuration management and automation tool.

It is used to:

  • Configure servers
  • Install software
  • Deploy applications
  • Enforce system state
  • Automate operational tasks

In DevOps terms:

Terraform → Creates infrastructure
Ansible → Configures infrastructure

2️⃣ Why DevOps Engineers Use Ansible

Without Ansible:

  • SSH into server
  • Install packages manually
  • Configure services manually
  • Risk human errors
  • No repeatability

With Ansible:

  • Infrastructure as Code
  • Repeatable configuration
  • Version controlled
  • Scalable automation

3️⃣ How Ansible Works

Architecture

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Ansible is:

  • Agentless
  • Push-based
  • Uses SSH

Components:

Control Node
→ Where Ansible runs (Mac, CI server, etc.)

Managed Nodes
→ Remote servers (EC2, VM, etc.)

Inventory
→ List of servers

Playbook
→ YAML automation file

Modules
→ Built-in automation tasks

4️⃣ Core Concepts Every DevOps Engineer Must Know

1. Inventory

Defines groups of servers.

Example:

[web]
3.141.22.178

[db]
3.141.22.200
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Why important:
You deploy different configurations to different environments.

2. Playbooks (YAML)

Playbooks define desired state.

Example:

- hosts: web
  become: yes
  tasks:
    - name: Install nginx
      apt:
        name: nginx
        state: present
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DevOps Insight:
This is declarative.
You define state, not commands.

3. Idempotency (VERY IMPORTANT)

If you run playbook 10 times:

Result = same state.

This is critical for production systems.

DevOps engineers must understand:
Automation must be safe to re-run.

4. Modules

Examples:

  • apt
  • yum
  • copy
  • file
  • service
  • user
  • git
  • docker_container

You must know how to read module documentation.

5. Variables

Used to make playbooks reusable.

Example:

vars:
  package_name: nginx
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Professional DevOps work heavily with variables.

6. Handlers

Handlers run only when triggered.

Example:

If config file changes → restart service.

This prevents unnecessary restarts.

Production best practice.

7. Roles (Production Structure)

Instead of one big playbook, companies use:

roles/
  nginx/
    tasks/
    handlers/
    vars/
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Roles = reusable automation components.

Every DevOps engineer should know roles.

8. Ansible vs Terraform (Important Interview Topic)

Terraform:

  • Provisions infrastructure
  • Cloud-focused
  • Creates EC2, VPC, etc.

Ansible:

  • Configures inside the server
  • Installs software
  • Manages services

They are complementary.

5️⃣ Real DevOps Use Cases

In real companies, Ansible is used for:

  • OS hardening
  • Patch management
  • Application deployment
  • CI/CD automation
  • Server configuration
  • Kubernetes node setup
  • Docker installation
  • Log configuration
  • Security compliance

6️⃣ Ansible in CI/CD

Ansible can run inside:

  • Jenkins
  • GitLab CI
  • GitHub Actions

Example flow:

Code push → CI builds Docker image → Ansible deploys to server

This is common in smaller companies without Kubernetes.

7️⃣ What You Should Know for Interviews

DevOps engineer must understand:

  • How inventory works
  • How SSH connection works
  • What idempotency means
  • Difference between ad-hoc and playbook
  • How handlers work
  • How variables work
  • What roles are
  • How to troubleshoot connection issues
  • How to structure project properly

8️⃣ Common Mistakes

  • Using shell instead of modules
  • Not using handlers
  • Hardcoding values
  • Not grouping servers
  • Ignoring idempotency
  • Running playbooks without understanding output

9️⃣ Ansible Execution Flow

  1. Read inventory
  2. Connect via SSH
  3. Gather facts
  4. Execute tasks
  5. Trigger handlers if needed
  6. Print result summary

10️⃣ Ansible Output Understanding

Example:

ok=3
changed=1
failed=0
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DevOps must understand:

ok → Already in correct state
changed → System modified
failed → Task failed

Lab: Install and Configure Nginx on EC2 Using Ansible

Lab Architecture

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Flow:

Mac (Control Node)
→ SSH
→ EC2 Instance (Managed Node)
→ Install Nginx automatically

Lab Objective

By the end of this lab, students will:

  • Install Ansible
  • Create inventory file
  • Write first playbook
  • Install Nginx on EC2
  • Verify deployment in browser

Step 1 – Launch EC2 Instance

In AWS:

  • AMI: Ubuntu 22.04
  • Instance type: t2.micro

  • Security Group:

    • Port 22 (SSH) – Your IP
    • Port 80 (HTTP) – Anywhere

  • Attach IAM Role (optional)

Make sure you can SSH:

ssh -i key.pem ubuntu@<EC2_PUBLIC_IP>
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Step 2 – Install Ansible (On Your Mac) 

brew install ansible
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Verify:

ansible --version
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Step 3 – Create Project Folder 

mkdir ansible-lab
cd ansible-lab
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Step 4 – Create Inventory File

Create file: inventory.ini

[web]
<EC2_PUBLIC_IP> ansible_user=ubuntu ansible_ssh_private_key_file=~/Downloads/key.pem
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Test connection:

ansible web -i inventory.ini -m ping
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Expected output:

SUCCESS
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If this works → SSH + Ansible are configured correctly.

Step 5 – Create First Playbook

Create file: install-nginx.yml

- name: Install and start Nginx
  hosts: web
  become: yes

  tasks:
    - name: Update apt
      apt:
        update_cache: yes

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

    - name: Start nginx
      service:
        name: nginx
        state: started
        enabled: yes
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Step 6 – Run Playbook 

ansible-playbook -i inventory.ini install-nginx.yml
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Students will see:

  • TASK [Update apt]
  • TASK [Install nginx]
  • TASK [Start nginx]

Step 7 – Verify

Open browser:

http://<EC2_PUBLIC_IP>
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You should see:

Welcome to Nginx

Step 8 – Make It More Real (Optional)

Modify playbook to deploy custom HTML page:

Add this task:

    - name: Create custom index page
      copy:
        dest: /var/www/html/index.html
        content: |
          <h1>Welcome to JumpToTech DevOps Lab</h1>
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Run again:

ansible-playbook -i inventory.ini install-nginx.yml
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Refresh browser.

  • Agentless automation
  • YAML basics
  • Infrastructure configuration
  • Idempotency (run playbook twice → no changes)
  • SSH automation
  • Real DevOps workflow

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