As container-based workloads become increasingly prevalent, ensuring the security of container images is crucial to avoid introducing vulnerabilities into your deployments. In this comprehensive guide, we’ll explore the best practices for managing and securing container images in Azure Kubernetes Service (AKS).

Secure the Images and Runtime

Best Practice Guidance:

  • Scan your container images for vulnerabilities.
  • Only deploy validated images.
  • Regularly update the base images and application runtime.
  • Redeploy workloads in the AKS cluster.

When adopting container-based workloads, it’s essential to verify the security of the images and runtime used to build your applications. To avoid introducing security vulnerabilities, you can follow these best practices:

  • Scan Container Images: Include a process in your deployment workflow to scan container images using tools like Twistlock or Aqua. These tools can identify and help remediate vulnerabilities in your container images.

  • Deploy Verified Images: Only allow verified, vulnerability-free images to be deployed in your AKS cluster. You can automate this process using a continuous integration and continuous deployment (CI/CD) pipeline.

  • Update Base Images and Runtimes: Regularly update the base images and application runtimes used in your container images. Security fixes and patches are typically included in these updates, so keeping your images up-to-date is crucial.

  • Redeploy Workloads: After updating base images or application runtimes, be sure to redeploy your workloads in the AKS cluster to ensure they’re running on the latest secure images.

Automatically Build New Images on Base Image Update

Best Practice Guidance:

  • As you use base images for application images, use automation to build new images when the base image is updated. Since updated base images typically include security fixes, update any downstream application container images.

Each time a base image is updated, you should also update any downstream container images that rely on that base image. Integrate this build process into your validation and deployment pipelines, such as Azure Pipelines or Jenkins. These pipelines will ensure your applications continue to run on the updated base images. Once your application container images are validated, you can then update your AKS deployments to use the latest secure images.

Azure Container Registry Tasks can also automatically update container images when the base image is updated. With this feature, you can build a few base images and keep them updated with bug and security fixes, ensuring your downstream container images benefit from these updates.

For more information about automating base image updates, see the Automate image builds on base image update with Azure Container Registry Tasks article.

Conclusion

Securing container images is a crucial aspect of running a secure and resilient AKS cluster. By following the best practices outlined in this guide, you can minimize the risk of vulnerabilities, keep your container images up-to-date, and maintain a high level of security throughout your container-based applications' lifecycle.

Remember, the earlier you can catch vulnerabilities or outdated base images, the more secure your applications will be. By integrating robust scanning and automated image update processes, you can stay ahead of potential security threats and ensure your AKS deployments are protected.

[Source: https://raw.githubusercontent.com/MicrosoftDocs/azure-docs/main/articles/aks/operator-best-practices-container-image-management.md]