Introduction

Microsoft's relationship with Linux has evolved significantly over the past two decades. Once seen as competitors, Microsoft now embraces Linux, especially within its Azure cloud platform. A testament to this transformation is the introduction of Azure Image Testing for Linux (AITL), a self-service validation tool designed to ensure that Linux virtual machine (VM) images meet Azure's stringent standards before deployment.

Background: The Need for AITL

As cloud computing and artificial intelligence continue to advance, delivering high-quality, secure, and reliable Linux VM images has become paramount. Before AITL, the validation of these images was predominantly manual, leading to several challenges:

  • Time-Consuming Processes: Manual validation delayed image releases.
  • Inconsistent Validation Methods: Different distributions employed varied testing methods, resulting in inconsistent quality.
  • Limited Scalability: Resource constraints hindered the validation of a broad set of images.

AITL addresses these challenges by automating the validation process, enabling developers, Independent Software Vendors (ISVs), and Linux distribution partners to integrate image validation seamlessly into their existing pipelines. This ensures compliance with Azure's best practices in a scalable and automated manner.

How AITL Works

AITL is powered by the Linux Integration Services Automation (LISA) framework, an open-source tool containing over 400 test cases. The workflow for AITL involves:

  1. Registration: Partners register their images within AITL's validation framework.
  2. Automated Testing: AITL executes a suite of predefined validation tests using LISA.
  3. Detailed Reporting: Developers receive comprehensive results highlighting compliance, performance, and security areas, with access to all test logs.
  4. Self-Service Fixes: Any detected issues can be addressed by the partner before submission, eliminating delays and back-and-forth communication.
  5. Final Sign-Off: Once tests pass, partners can confidently publish their images, knowing they meet Azure's quality standards.

Benefits of AITL

AITL offers several advantages:

  • Self-Service Capability: Enables developers and ISVs to independently validate their images without direct support from Microsoft.
  • Scalability: Supports concurrent testing of multiple images, enhancing operational efficiency.
  • Consistent and Standardized Testing: Provides a unified validation framework to ensure quality across all endorsed Linux distributions.
  • Proactive Issue Detection: Identifies potential issues early in the development cycle, preventing costly post-deployment fixes.
  • Seamless Pipeline Integration: Easily integrates with existing CI/CD workflows for fully automated image validation.

Use Cases for AITL

AITL is designed to support a diverse set of users:

  • Linux Distribution Partners: Organizations like Canonical, Red Hat, and SUSE can validate their images before publishing on the Azure Marketplace, ensuring they meet Azure's quality and compliance standards.
  • Independent Software Vendors (ISVs): Companies providing custom Linux images can verify that their solutions are optimized for performance and reliability on Azure.
  • Enterprise IT Teams: Businesses managing their own Linux images on Azure can use AITL to proactively validate updates, reducing risk and ensuring smooth production deployments.

Current Status and Future Roadmap

As of April 2025, AITL is in private preview, with five major Linux distributions and select ISVs actively integrating it into their validation workflows. Microsoft plans to expand AITL's capabilities by adding:

  • Support for Private Test Cases: Allowing partners to run custom tests within AITL securely.
  • Kernel Continuous Integration (CI) Integration: Enhancing low-level kernel validation for more robust testing and results for the community.
  • Data Plane Development Kit (DPDK) and Specialized Validation: Ensuring network and hardware performance for specialized SKUs and workloads.

Getting Started with AITL

For developers and partners interested in AITL, the onboarding process involves:

  1. Registering for Private Preview: Contact Microsoft's Linux Systems Group to request access.
  2. Setting Up Permissions: Assign the necessary roles and permissions to enable AITL to create test resources within your Azure subscription.
  3. Creating a Test Job: Use the AITL wrapper to create and manage test jobs, specifying the image and test parameters.
  4. Reviewing Test Results: Access detailed test results and logs to identify and address any issues before publishing the image.

By following these steps, partners can leverage AITL to ensure their Linux VM images meet Azure's quality standards, enhancing reliability and performance for end-users.

Conclusion

AITL represents a significant advancement in Linux image validation, bringing automation, scalability, and consistency to the forefront. By shifting validation earlier in the development cycle, AITL helps reduce risk, accelerate time to market, and ensure a reliable, high-quality Linux experience on Azure. Whether you're a developer, a Linux distribution partner, or an enterprise managing Linux workloads on Azure, AITL offers a powerful way to modernize and streamline your validation workflows.