Understanding AMIs - Your Server’s Starting Point

Lesson 5

Ready to learn about one of the most important concepts in cloud computing? An Amazon Machine Image (AMI) is like a template or recipe for creating servers. Just like a cookie cutter shapes cookies, an AMI shapes what your server looks like when it starts up.

Think of it this way:

AMI = Server Template: Contains the operating system, software, and initial setup
Your Phone’s Factory Reset: When you reset your phone, it goes back to how it came from the factory
Server Blueprints: AMIs are the blueprints that tell AWS exactly how to build your server

Why are AMIs important? Instead of manually installing an operating system, web server software, and applications on every new server, you can choose an AMI that already has everything pre-installed. It’s like buying a pre-furnished apartment instead of an empty room!

Common AMI types include:

Basic Operating Systems: Linux, Ubuntu, Windows Server (like a blank canvas)
Web Servers: Pre-configured with Apache or Nginx (ready to serve websites)
Application Stacks: WordPress, databases, development environments (fully-loaded with specific software)
Custom Images: Your own saved configurations (like your personal server template)

Important: AMIs Are Region-Specific

New to AWS regions? Check out AWS Fundamentals for a quick overview of regions and other core concepts. Don’t worry if you haven’t read it yet - we’ll explain what you need to know here!

Here’s something crucial to understand: Each AMI has a different ID in each AWS region. Think of it like postal codes - the same McDonald’s franchise might exist in different cities, but each location has a different address.

What this means for you:

An AMI ID that works in us-east-1 (Virginia) won’t work in us-west-2 (Oregon)
You need to find the correct AMI ID for your specific region
If you get an “AMI not found” error, you’re probably using the wrong region’s ID

Real-world example:

Amazon Linux in Virginia: ami-0c02fb55956c7d316
Amazon Linux in Oregon: ami-0efcece6bed30fd98
Same AMI, different locations, different IDs!

Understanding AMIs - Your Server’s Starting Point
1. Important: AMIs Are Region-Specific
Finding the Perfect AMI for Your Project
1. Step 1: Subscribe to a WordPress AMI
Step 2: Create a WordPress Site with Terraform
What You’ve Accomplished

Finding the Perfect AMI for Your Project

AWS offers thousands of pre-built AMIs, like a massive app store for servers. Some are free (like basic Linux), others cost money (like specialized software), and some require a one-time “subscription” to use.

Why search for AMIs?

Save time: Instead of installing WordPress manually, use a WordPress AMI
Get started faster: Someone else already did the hard setup work
Professional quality: Many AMIs are maintained by software companies

Today’s mission: We’ll find and use a WordPress AMI to create a fully-functional website in minutes!

Some AMIs require a one-time “subscription” (like accepting terms of service) before you can use them. We’ll do this by launching one instance manually, then we can use it in Terraform forever.

Think of it like: Downloading an app from the app store - you agree to the terms once, then you can use it anytime. Follow these steps to subscribe to WordPress:

Log into AWS Console
- Use your bookmarked AWS Console link
Go to EC2
- Search “EC2” in the top search bar
- Click “EC2” from the results
- Click “Instances” in the left sidebar
Start Launching an Instance
- Click the orange “Launch instances” button (top right)
Search for WordPress
- You’ll see “Choose an Amazon Machine Image (AMI)” at the top
- In the search box, type: wordpress
- Click “AWS Marketplace” in the left sidebar (important!)
Select WordPress AMI
- Find “WordPress Certified by Bitnami and Automattic”
- Click “Select” on that option
- Click “Continue” when the pricing popup appears
Quick Setup (we’ll delete this right away)
- Instance type: Choose t2.micro (free tier)
- Click “Review and Launch” (orange button)
Launch It
- Click “Launch”
- Choose your key pair from dropdown (the one you created earlier)
- Check the acknowledgment box
- Click “Launch instances”
Get the AMI ID (This is what we really need!)
- Click “View instances”
- Click on your new instance’s ID (blue link)
- In the “Details” tab, find “AMI ID”
- Copy this AMI ID - you’ll need it next!

wordpress ami

Congratulations! You’ve just subscribed to a WordPress AMI. This process works for any AMI in the AWS Marketplace.

Common AMI types you’ll encounter:

Amazon Linux 2: What we’ve been using (basic, reliable, AWS-optimized)
Ubuntu: Popular Linux distribution (developer-friendly)
Windows Server: For .NET applications and Windows-specific software
Application AMIs: WordPress, databases, development environments

Important: Now delete this test instance to avoid charges:

Click “Instance state” dropdown (top right)
Choose “Terminate instance”
Confirm the termination

What just happened? You subscribed to the WordPress AMI, which means you can now use it in Terraform anytime. The AMI ID you copied is your key to creating WordPress sites with code!

Step 2: Create a WordPress Site with Terraform

Now for the magic! Let’s use Terraform to deploy a WordPress website using the AMI you just subscribed to. This is where variables really shine - we only need to change one line!

Update Your Terraform Project

Remember your Terraform project? We’re going to modify it to use WordPress instead of our basic web server.

Change the AMI ID

Open your project
- Open your code editor
- Navigate to your my-first-ec2 project folder
Update the AMI variable
- Open terraform.tfvars (this is where you set variable values)
- Find the line that says: ami = "ami-0c02fb55956c7d316"
- Replace it with your WordPress AMI ID: ami = "YOUR_COPIED_AMI_ID"
Quick reference: If you’re using us-east-1, the WordPress AMI ID is: ami-0c00935023a833df1
Remove the web server setup code
- Open ec2.tf
- Find the user_data section (the script that installed web server software)
- Comment it out (don’t delete it - we’ll need it later!)

How to comment out code:

Select the user_data lines
Press Ctrl + / (Windows/Linux) or Cmd + / (Mac)
You’ll see // appear at the start of each line
Terraform will ignore commented lines (they turn gray/green in most editors)

wordpress ami 1

Deploy Your WordPress Site

Time to see the magic happen! We’re about to create a fully-functional WordPress website with just a few commands.

Deploy your site:

Check your location

pwd  # Should show your project directory
cd my-first-ec2  # Navigate here if needed

Deploy with Terraform
```
terraform apply
```
Confirm deployment
- Type yes when prompted
- Wait for “Apply complete!” message

terraform apply wordpress

See Your WordPress Site Live!

Verify your deployment:

Check in AWS Console
- Go to EC2 → Instances
- Click on your instance
- Verify the AMI ID matches what you set
- Copy the “Public IPv4 address”
Visit your WordPress site
- Paste the IP address into a new browser tab
- Press Enter

Amazing! Instead of our simple “Hello World” page, you now have a fully-functional WordPress website complete with:

WordPress login system
Content management interface
Database backend
Web server configuration
Security settings

wordpress site

What just happened? You deployed enterprise-grade software in minutes using Infrastructure as Code. This is the power of AMIs - complex software stacks become as easy as changing one variable!

Clean Up

terraform destroy

Type yes to delete your WordPress site and avoid charges.

What You’ve Accomplished

✅ Learned the concept of AMIs - Server templates that save massive amounts of time
✅ Understood region-specific IDs - Why the same AMI has different IDs in different locations
✅ Navigated AWS Marketplace - Found and subscribed to third-party AMIs
✅ Deployed complex software - Created a WordPress site in minutes instead of hours
✅ Experienced the power of variables - Changed one line to completely transform your infrastructure
✅ Managed AMI lifecycles - From subscription to deployment to cleanup

You’ve just experienced one of cloud computing’s biggest advantages: The ability to deploy complex, production-ready software stacks instantly using pre-built templates.

The Big Picture

What you learned applies everywhere:

Time-saving: AMIs eliminate hours of manual software installation
Consistency: Same setup every time, no human error
Professional workflows: This is how companies deploy software at scale
Cost management: Pre-built AMIs often save more money than they cost

Practice Options

Option 1: Try Different AMIs (Recommended)

Explore the AWS Marketplace and try different AMIs:

Database AMIs: MySQL, PostgreSQL, MongoDB
Development AMIs: Node.js, Python, Ruby environments
Security AMIs: VPN servers, security tools
CMS AMIs: Drupal, Joomla, other content management systems

Option 2: Reset and Repeat

Want to practice the process again?

Change your AMI back to: ami-0947d2ba12ee1ff75
Uncomment your user_data (select it and press Ctrl + / or Cmd + /)
Run terraform apply to get back to your basic web server
Repeat this lesson from the beginning

Next Steps

Ready to learn about server sizes and performance? Head to Instance Types where you’ll discover how to choose the right computational power for your applications!

Pro Tip: AMIs are like having a team of system administrators who pre-configured everything perfectly. You’re now thinking like a cloud architect!