Engineering Blog


Automating Docker Security with Kaniko, Cosign, Kyverno

In the world of software development, delivering high-quality software quickly, securely, and reliably is paramount. Docker images simplify deployment, but they can also introduce challenges. This blog post explores how to automate these procedures to maximize the benefits of Docker images, using real-world examples from  BIOCAD, a biotech company.

Building Secure Docker Images with Kaniko

Manually building Docker images can be time-consuming and inconsistent. Kaniko, a tool developed by Google, addresses this by creating Docker images directly within Kubernetes clusters. This offers several advantages:

  • Security: Kaniko eliminates the need for a Docker daemon, reducing potential security risks in the build environment.
  • Efficiency: Kaniko builds images accurately and efficiently, replicating the functionality of Docker.
  • Integration: Kaniko integrates seamlessly with GitLab CI/CD pipelines.

Here’s a GitlabCI configuration snippet demonstrating how to use Kaniko for building Docker images:


  stage: "build"
    name: ""
    entrypoint: [""]
  # ... (script section with build arguments and Kaniko commands)

Signing Docker Images for Trust with Cosign

Cosign, an open-source tool, helps ensure the integrity and provenance of Docker images. It allows you to sign images, verifying their source and preventing them from being tampered with. Cosign integrates well with existing workflows and can be automated as part of a CI/CD pipeline.

Here’s how to set up a GitLab CI job to sign Docker images using Cosign:


  image: bitnami/cosign:2.2.0-debian-11-r31
  stage: sign
  # ... (script section with secrets loading, signing, and verification)

Enforcing Image Signing with Kyverno

 Kyverno is a Kubernetes policy management tool that helps maintain best practices within your cluster. It can be used to enforce image signing, ensuring only signed images are deployed. Kyverno’s native Kubernetes integration simplifies its use.

Here’s a YAML snippet showcasing a Kyverno ClusterPolicy that verifies image signatures:


kind: ClusterPolicy
# ... (policy configuration including image verification rules)

This policy ensures that any pod created or updated in the cluster using images matching a specified pattern will be verified using the provided public key before being allowed to run.

Putting It All Together

By combining these tools, we can create a secure and automated pipeline for building, signing, and verifying Docker images. Here’s an overview of the workflow:

  1. Build: The GitLab CI pipeline utilizes Kaniko to build the Docker image securely within the Kubernetes cluster.
  2. Sign: Cosign signs the built image, guaranteeing its authenticity and preventing unauthorized modifications.
  3. Verify: Kyverno enforces a policy in the Kubernetes cluster, ensuring only signed images are deployed.

Benefits and Conclusion

This approach offers several benefits:

  • Improved Security: Signing images and enforcing signing policies significantly reduces the risk of deploying tampered or unauthorized images.
  • Enhanced Efficiency: Automating the build, sign, and verify process streamlines the workflow and saves time.
  • Increased Consistency: Automation ensures consistent image handling throughout the development lifecycle.

By incorporating these tools and techniques, BIOCAD has enhanced the efficiency, security, and consistency of its Docker image management process. This approach can be valuable for any organization seeking to streamline and secure their software deployments.

Reference to the Article- Medium

Follow us for more updates!

Previous Post
Next Post