🛠️ Automate AMI Builds with Packer + EC2 Image Builder

#aws #devops #terraform #crosscloudx

📦 DevOps Battle for Golden Images in AWS

🧭 1. Why Automate AMI Builds?

Golden AMIs ensure that all your EC2 instances start with consistent, hardened, and pre-configured environments.

❌ Manual builds = human errors, time waste, inconsistent images

✅ Automated builds = repeatable, secure, auditable

⚔️ 2. Packer vs EC2 Image Builder: The Showdown

Feature	🧰 Packer	🖼️ EC2 Image Builder
🔧 Configuration Language	JSON or HCL	YAML or Console
🔄 Integration with CI/CD	✅ Very flexible	⚠️ Limited (manual triggers, EventBridge workaround)
🛡️ Security Controls	✅ Custom via hardening scripts	✅ SSM + IAM roles
📦 Output Formats	AMIs, Docker, Vagrant, etc.	AMIs (only)
☁️ AWS Native	❌ Third-party tool	✅ Fully managed
📜 Logging & Visibility	CLI or external	✅ CloudWatch logs, detailed history
🧪 Testing AMIs	Manual or via external tools	✅ Supports testing phases (e.g., InSpec)
💰 Cost	Low (runs in your own infra)	Low, but requires pipeline resources

🏁 TL;DR:

Use Packer when you need portability and full control.

Use EC2 Image Builder when you prefer AWS-native, low-maintenance pipelines.

🔧 3. Demo: Building a Hardened Ubuntu AMI in Both Tools

Option A: Using Packer + HCL

Define ubuntu.pkr.hcl:

packer {
  required_plugins {
    amazon = {
      version = ">= 1.2.8"
      source  = "github.com/hashicorp/amazon"
    }
  }
}

source "amazon-ebs" "ubuntu" {
  ami_name      = "learn-packer-linux-aws"
  instance_type = "t2.micro"
  region        = "us-west-2"
  source_ami_filter {
    filters = {
      name                = "ubuntu/images/*ubuntu-jammy-22.04-amd64-server-*"
      root-device-type    = "ebs"
      virtualization-type = "hvm"
    }
    most_recent = true
    owners      = ["099720109477"]
  }
  ssh_username = "ubuntu"
}

build {
  name    = "learn-packer"
  sources = ["source.amazon-ebs.ubuntu"]
  provisioner "shell" {
    inline = [
      "sudo apt-get update",
      "sudo apt-get install -y nginx",
    ]
  }
}

Build the image:

packer init .
packer build ubuntu.pkr.hcl

Option B: Using EC2 Image Builder

Create a Recipe

Example component in YAML:

name: install-nginx
description: Install Nginx
phases:
  build:
    commands:
      - apt update
      - apt install -y nginx

Create a Pipeline with:

Source AMI: Ubuntu 22.04
Build Component: install-nginx
Test Component (optional): e.g., check Nginx service
Output: AMI in target region

Trigger manually or via EventBridge for automation (e.g., weekly builds)

🎯 5. Conclusions & Recommendations

Verdict:

🧰 Use Packer if:

You want cross-cloud image creation

You need integration with existing pipelines

You're comfortable managing infrastructure

🖼️ Use EC2 Image Builder if:

You're all-in on AWS

You want minimal setup with native controls

You want to integrate with AWS Config, IAM, and SSM easily