Automation with Hashicorp Packer #13: AWS Authentication

Introduction

In this tutorial, we will explore how to handle AWS authentication securely while using Hashicorp Packer. Packer is a powerful tool for creating custom images across various cloud platforms. This guide will walk you through the steps necessary to set up AWS authentication with a focus on security best practices.

Step 1: Set Up AWS Credentials

To authenticate with AWS using Packer, you need to configure your AWS credentials. This can be done through the AWS Management Console or by using the AWS CLI.

1. Create an IAM User:

   • Log in to the AWS Management Console.
   • Navigate to IAM (Identity and Access Management).
   • Click on "Users" and then "Add user."
   • Set a username and select "Programmatic access" as the access type.

2. Set Permissions:

   • Attach policies that provide the necessary permissions for Packer. Commonly used policies include:
     • AmazonEC2FullAccess
     • AmazonS3FullAccess
   • Click "Next" and review the settings, then create the user.

3. Save Access Keys:

   • After creating the user, save the Access Key ID and Secret Access Key. You will use these credentials in your Packer configuration.

Step 2: Configure AWS Authentication in Packer

Next, you'll need to set up your Packer template to use the AWS credentials securely.

1. Create Packer Template File:

   • Create a JSON or HCL file for your Packer template.
   • Here’s an example of a minimal Packer configuration in JSON format:

   {
     "builders": [
       {
         "type": "amazon-ebs",
         "access_key": "YOUR_ACCESS_KEY",
         "secret_key": "YOUR_SECRET_KEY",
         "region": "us-east-1",
         "source_ami": "ami-0c55b159cbfafe1f0",
         "instance_type": "t2.micro",
         "ssh_username": "ubuntu",
         "ami_name": "my-custom-image {{timestamp}}"
       }
     ]
   }
   

2. Use Environment Variables for Security:

   • Instead of hardcoding the access and secret keys, set them as environment variables in your terminal:

   export AWS_ACCESS_KEY_ID=your_access_key
   export AWS_SECRET_ACCESS_KEY=your_secret_key
   

3. Modify Packer Template to Use Environment Variables:

   • Update your template to reference the environment variables:

   {
     "builders": [
       {
         "type": "amazon-ebs",
         "access_key": "{{env `AWS_ACCESS_KEY_ID`}}",
         "secret_key": "{{env `AWS_SECRET_ACCESS_KEY`}}",
         "region": "us-east-1",
         "source_ami": "ami-0c55b159cbfafe1f0",
         "instance_type": "t2.micro",
         "ssh_username": "ubuntu",
         "ami_name": "my-custom-image {{timestamp}}"
       }
     ]
   }
   

Step 3: Test the Configuration

Once your template is set up, it's time to validate the configuration.

1. Validate Packer Template:

   • Open a terminal and run the following command to validate your Packer configuration:

   packer validate your-template.json
   

2. Build the Image:

   • If validation is successful, you can build your image using:

   packer build your-template.json
   

Conclusion

In this tutorial, we've covered how to securely authenticate with AWS using Hashicorp Packer. By creating an IAM user with appropriate permissions and using environment variables for your AWS credentials, you can safeguard your sensitive information while automating image creation.

As a next step, consider exploring how to customize your Packer templates further or integrate them with CI/CD pipelines for automated deployments.