Configure Notary for Image Signing | Secure Your Containers

How to Configure Notary for Image Signing

In modern software development, especially with containers, securing image provenance through signing is crucial. Docker’s Notary tool offers an efficient solution to this by providing a means to sign images, ensuring their authenticity and integrity. This tutorial walks you through the process of setting up and configuring Notary for image signing.

Prerequisites

A basic understanding of Docker and containers
Docker CLI installed (Docker CLI Official site)
Notary client installation (Notary GitHub Dashboard)

Step-by-Step Configuration

Step 1: Install Notary Client

To begin, you’ll need to install the Notary client. This can be done using the go-to tools on your terminal.

brew install notary

If you’re on a Linux distribution, use:

apt-get install notary

Step 2: Create a Notary Repository

Notary works by managing signed images in repositories. Use the command below to initialize a new notary repository:

notary init example.com/demo

Ensure you replace example.com/demo with your actual image repository reference.

Step 3: Generate Signed Delegation Keys

Delegation keys are essential for signing and verifying contents in your repository. Use the command:

notary delegation add example.com/demo targets/releases keys.json

The keys.json file should contain your cryptographic keys, which must be securely stored.

Step 4: Sign an Image

After initializing the repository and keys, you can sign an image using:

docker push example.com/demo:latest

This command allows you to push and automatically sign the image.

Step 5: Verify the Signed Image

Use the verification command to confirm the integrity of your signed image:

notary verify example.com/demo latest

This ensures that the signature matches and the image is unaltered.

Troubleshooting Tips

If you encounter issues, here are some common solutions:

Verify that your Docker client is properly configured to use the Notary service.
Ensure all delegation keys are correct and up to date.
Check network connectivity if signing or verification steps hang indefinitely.

Summary Checklist

Install Notary and Docker CLI
Initialize the Notary repository
Generate and manage delegation keys
Sign Docker images using Notary
Verify signed images for integrity

By following these steps, you can ensure the integrity and authenticity of your Docker images, protecting your deployment environments. For more on container security, check our guide on installing Anchore for security scanning.