How to Create Custom AWS AMIs with Packer – Step-by-Step Tutorial

*Originally published on [DevTutsPro]

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1. Why Create Custom AMIs?

Building your own Amazon Machine Images (AMIs) offers several advantages:

• 🚀 Faster EC2 launches – pre-configured images save boot time.

• 🔄 Eliminate repetitive setup – no more manual installation for each instance.

• 📦 Consistent environments – identical setups across production, staging, and development.

In this guide, you’ll discover how to:

• Create a custom AWS AMI using Packer.

• Automatically install essential tools like Git and Docker.

• Learn why Packer outperforms manual AMI creation.

• Properly test and clean up AWS resources after the build.

2. Initial Setup: EC2 Instance + Packer

• Launch a Base EC2 Instance (t2.micro)

• AMI: Amazon Linux 2

• Instance Type: t2.micro

• Key Pair: Ensure SSH access (port 22)

Installing Packer on EC2

For Amazon Linux / RHEL:

sudo yum update -y sudo yum install -y yum-utils unzip curl -fsSL https://apt.releases.hashicorp.com/gpg | sudo gpg --dearmor -o /usr/share/keyrings/hashicorp-archive-keyring.gpg sudo yum-config-manager --add-repo https://rpm.releases.hashicorp.com/AmazonLinux/hashicorp.repo sudo yum install packer -y

For Ubuntu/Debian:

sudo apt-get update && sudo apt-get install -y gnupg software-properties-common curl curl -fsSL https://apt.releases.hashicorp.com/gpg | sudo gpg --dearmor -o /usr/share/keyrings/hashicorp-archive-keyring.gpg echo "deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] https://apt.releases.hashicorp.com $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/hashicorp.list sudo apt update && sudo apt install packer -y

Check Version:

packer --version

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3. IAM Role Creation

Create an IAM role with the following settings:

• Trusted Entity: EC2

• Attach Policies:

• AmazonEC2FullAccess

• AmazonSSMFullAccess

• IAMInstanceProfileRole

• (Optional) AmazonS3FullAccess

Attach this role to your EC2 instance that will run Packer.

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4. Create Your Packer Template

ami.pkr.hcl File:

packer { required_plugins { amazon = { version = ">= 0.0.2" source = "github.com/hashicorp/amazon" } } }

source "amazon-ebs" "amazon-linux" { region = "ap-southeast-2" ami_name = "ami-version-1.0.1-{{timestamp}}" instance_type = "t2.micro" source_ami = "ami-0d6294dcaac5546e4" ssh_username = "ec2-user" ami_regions = ["ap-southeast-2"] }

build { name = "hq-packer" sources = ["source.amazon-ebs.amazon-linux"]

provisioner "file" { source = "provisioner.sh" destination = "/tmp/provisioner.sh" }

provisioner "shell" { inline = [ "chmod a+x /tmp/provisioner.sh", "ls -la /tmp", "pwd", "cat /tmp/provisioner.sh", "/bin/bash -x /tmp/provisioner.sh" ] } }

provisioner.sh File:

#!/usr/bin/env bash

# Update packages sudo yum -y update

# Install Git sudo yum install git -y

# Install Docker sudo yum install docker -y sudo systemctl start docker

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5. Build the AMI with Packer

packer init . packer validate ami.pkr.hcl packer build ami.pkr.hcl

This will:

• Launch a temporary EC2 instance

• Execute the provisioning script

• Create a new AMI

• Terminate the temporary instance

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6. Check the Created Resources

View AMI in AWS Console:

1. Open the EC2 Dashboard

2. In the left sidebar, click AMIs

3. Filter by Owned by Me

4. Look for an AMI named similar to:
   ami-version-1.0.1-<timestamp>

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7. Clean Up Unused Resources

Why Cleanup Is Important

Leaving unused AMIs and snapshots increases costs and clutter. Always delete temporary resources when no longer needed.

Steps to Clean Up Resources

Delete the Custom AMI:

1. Go to EC2 → AMIs

2. Select the custom AMI (e.g., ami-version-1.0.1-<timestamp>)

3. Click Actions → Deregister AMI

Delete Associated Snapshots:

1. Go to EC2 → Snapshots

2. Find the snapshot linked to the AMI (check description)

3. Select it → Click Actions → Delete Snapshot

Confirm Temporary EC2 Termination:

• Go to EC2 → Instances

• Filter by name or recently created instances

• Confirm that no temporary instance from the build is running

• If you find one still running, terminate it manually

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8. Conclusion

Using Packer to create custom AWS AMIs provides:

• ⚡ Faster EC2 instance launches – reduce startup time with pre-baked configurations.

• 🔄 Consistent, automated builds – eliminate human errors and ensure identical environments.

• 🚀 Seamless CI/CD integration – easily fit into modern DevOps workflows.

Whether you’re deploying to production, staging, or testing, Packer makes your infrastructure repeatable, reliable, and cost-efficient.

📝 Read the full original post here: https://www.devtutspro.in/2025/08/creating-custom-amis-with-packer-step.html