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.

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.