Packer Alternative: Migrating to AWS EC2 Image Builder for Automated AMI Pipelines

Introduction

HashiCorp Packer is one of the most popular open-source machine image builders. It helps engineers define infrastructure as code, installing software and layering security updates into AWS Machine Images, or AMIs. Packer is focused on image building. It has no capabilities around testing, scheduling, AWS notifications, or distribution.

On the other hand, AWS EC2 Image Builder is a fully managed service that automates the creation, testing, hardening, and distribution of AMIs. It conveniently integrates with AWS services, such as EventBridge, SNS, Systems Manager (SSM), and IAM, enabling greater automation of security enforcement policy, pipeline automation, and lowered operational workload.

In this blog, we will carry out a comparison of Packer with EC2 Image Builder and reason out the value of migrating over to EC2 Image Builder.

Packer Overview

Packer can facilitate faster creation of AMIs through automation of software installation and OS hardening. It used an HCL template to write an automation script to build a Golden AMI.

There are some operational challenges as well:

• Scheduling: lacks any built-in scheduling capabilities. External cron or CI/CD systems are a must.
• Testing: requires manual testing of the completed images after building.
• Distribution: Want your AMI in multiple accounts or regions? Be ready for some scripting.
• Custom notifications: Requires EventBridge + SNS rules that you have to stitch together yourself.
• Complex setup: IAM, networking, and orchestration all need manual care.
• Manual AMI updates: Engineers often fetch the latest AMI IDs (via SSM)

To summarise, a lot of extra work is needed to make Packer function

Packer

Entering into EC2 Image Builder:

It’s a fully managed AWS service for building, testing, securing, and distributing AMIs.
This managed service provides the following features:

• CI/CD Pipeline – Equivalent to a pipeline for end-to-end AMI deployment.
• AMI Distribution – Provide an easy way for cross-account sharing as well.
• Build Schedule – Job schedule and cron expression methods.
• SNS Notifications – Notify on the success or failure events of the AMI.
• Networking –  IAM & VPC integration

EC2 Image Builder Configuration

EC2 Image Builder consists of various sub-resources that need to be defined:

• Components: Use custom scripts or AWS-managed scripts for hardening and patching the AMI.
• Image/container recipe: managed base image or custom image selection, EBS configuration, and directory path to store files and add the components.
• Infrastructure Configuration: Since the AMI is built inside the private network, we can choose the instance type and make it more secure by passing the IAM role as well, with appropriate permissions.
• Distribution Settings: This helps to set the AMI name and tagging. Also, distribution of the AMI to cross regions and accounts, launch template or SSM parameter. It helps enforce the standards followed at every deployment.
• Image Workflow:
  • Build Image – the custom/managed scripts patch, install and harden the AMI.
  • Test Image – After the AMI build, the server can be launched to run validation scripts compliance checks, and before distributing to the organisation.
• Image Pipeline: This uses all the above-mentioned resources and works as a CI/CD pipeline to fetch, build, test and push the AMI to the destination. This Pipeline has an inbuilt and out-of-the-box feature to schedule itself via cron

EC2 Image Builder

Why EC2 Image Builder?

1. Provides Faster Builds
   1. No additional server required with Serverless orchestration.
   2. Builds and testing occur on AWS-managed EC2 instances.
2. It’s a Cost-Effective
   1. Pay only for EC2, EBS and S3 subsystems.
   2. No private CI/CD orchestration is required.
3. More Secure setup
   1. Works with IAM policies and roles.
   2. Builds run in private subnets with no need for public IPs.
   3. Images with in-built compliance and signing capabilities.
4. Increased Reliability
   1. Continuous feature additions with AWS managed service.
   2. Cross-account, cross-region AMI distribution for large companies.
5. Complete Pipeline
   1. Integrated distribution and validation of the Output AMIs
   2. Post-build testing workflows are included out of the box.

Advantages of EC2 Image Builder

• Functions as a full CI/CD pipeline for AMIs.
• Supports schedule options to auto-trigger itself.
• Ensure that the latest Amazon Linux and Windows AMIs are fetched every time.
• Offer custom scripts and many cloud-managed components such as aws-cli, CloudWatch Agent, SSM Agent, and CodeDeploy agent to pre-configure them on the golden AMI.
• It simplifies and automates the distribution of the AMI.
• It supports integration with SNS to deliver and notify the AMI details on failure and success events
• Tags add-on before distribution of the Golden AMI to provide consistency

Wrapping Up

Packer is still a great tool, especially for multi-cloud environments or if you need complete control. But if your infrastructure is all-in on AWS, EC2 Image Builder is the clear choice.

It cuts down on overhead, bakes in best practices, and gives you a secure, automated pipeline for AMI management—without having to stitch multiple services together.

So instead of asking “should I switch?” the better question might be:

👉 “Why am I still managing this complexity manually?”

Stay tuned for Part 2, where we’ll walk through a real-world use case and a step-by-step hands-on setup.