Packer AWS AMI BuilderSkill

---
name: aws-ami-builder
description: Build Amazon Machine Images (AMIs) with Packer using the amazon-ebs builder. Use when creating custom AMIs for EC2 instances.
metadata:
  lifecycle-status: active
---

# AWS AMI Builder

Build Amazon Machine Images (AMIs) using Packer's `amazon-ebs` builder.

**Reference:** [Amazon EBS Builder](https://developer.hashicorp.com/packer/integrations/hashicorp/amazon/latest/components/builder/ebs)

> **Note:** Building AMIs incurs AWS costs (EC2 instances, EBS storage, data transfer). Builds typically take 10-30 minutes depending on provisioning complexity.

## Basic AMI Template

```hcl
packer {
  required_plugins {
    amazon = {
      source  = "github.com/hashicorp/amazon"
      version = "~> 1.3"
    }
  }
}

variable "region" {
  type    = string
  default = "us-west-2"
}

locals {
  timestamp = regex_replace(timestamp(), "[- TZ:]", "")
}

source "amazon-ebs" "ubuntu" {
  region        = var.region
  instance_type = "t3.micro"

  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"] # Canonical
  }

  ssh_username = "ubuntu"
  ami_name     = "my-app-${local.timestamp}"

  tags = {
    Name      = "my-app"
    BuildDate = local.timestamp
  }
}

build {
  sources = ["source.amazon-ebs.ubuntu"]

  provisioner "shell" {
    inline = [
      "sudo apt-get update",
      "sudo apt-get upgrade -y",
    ]
  }
}
```

## Common Source AMI Filters

### Ubuntu 22.04 LTS
```hcl
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"] # Canonical
}
```

### Amazon Linux 2023
```hcl
source_ami_filter {
  filters = {
    name                = "al2023-ami-*-x86_64"
    root-device-type    = "ebs"
    virtualization-type = "hvm"
  }
  most_recent = true
  owners      = ["amazon"]
}
```

## Multi-Region AMI

```hcl
source "amazon-ebs" "ubuntu" {
  region        = "us-west-2"
  instance_type = "t3.micro"

  source_ami_filter {
    filters = {
      name = "ubuntu/images/*ubuntu-jammy-22.04-amd64-server-*"
    }
    most_recent = true
    owners      = ["099720109477"]
  }

  ssh_username = "ubuntu"
  ami_name     = "my-app-${local.timestamp}"

  # Copy to additional regions
  ami_regions = ["us-east-1", "us-east-2", "eu-west-1"]
}
```

## Authentication

Packer uses AWS credential resolution:

1. Environment variables: `AWS_ACCESS_KEY_ID`, `AWS_SECRET_ACCESS_KEY`
2. AWS credentials file: `~/.aws/credentials`
3. IAM instance profile (when running on EC2)

```bash
export AWS_ACCESS_KEY_ID="your-access-key"
export AWS_SECRET_ACCESS_KEY="your-secret-key"
export AWS_REGION="us-west-2"

packer build .
```

## Build Commands

```bash
# Initialize plugins
packer init .

# Validate template
packer validate .

# Build AMI
packer build .

# Build with variables
packer build -var "region=us-east-1" .
```

## Common Issues

**SSH Timeout**
- Ensure security group allows SSH (port 22)
- Verify subnet has internet access

**AMI Already Exists**
- AMI names must be unique
- Use timestamp in name: `my-app-${local.timestamp}`

**Volume Size Too Small**
- Check source AMI's volume size
- Set `launch_block_device_mappings.volume_size` accordingly

## References

- [Amazon EBS Builder](https://developer.hashicorp.com/packer/integrations/hashicorp/amazon/latest/components/builder/ebs)
- [AWS AMI Documentation](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AMIs.html)