This article details how Uber successfully migrated one million lines of JUnit code in just two weeks using the Moderne platform. It highlights the strategies and tools employed during the migration process. The focus is on the practical aspects of large-scale code modernization.

The article discusses the migration of over 30 Kubernetes clusters to Terraform, detailing the challenges faced with previous tools like Sceptre and AWS CDK, and outlining a structured, iterative approach to the transition. Key strategies included automating processes, ensuring safety during rollbacks, and emphasizing hands-on knowledge transfer over traditional documentation. The authors share insights on tooling, risk management, and team collaboration throughout the migration journey.

Terraform migrate 1.1 introduces support for version control system (VCS) workspaces, enabling Git-based infrastructure management and automated migration flows. It improves user experience with features like token validation optimization and reliable branch pushing, streamlining the migration process to HCP Terraform and Terraform Enterprise.

Uber successfully upgraded over 2 million Apache Spark applications from version 2.4 to 3.3, leveraging innovative automation tools like Iron Dome and Polyglot Piranha to manage the complex migration process. The transition resulted in significant efficiency gains, including a 50% reduction in runtime and resource usage, and paved the way for future upgrades and optimizations.