How to Plan a Successful CI/CD Migration Without Disruption

CI/CD migration is a complex process that involves transitioning the systems that validate pull requests, produce artifacts, and promote releases to production. To ensure a smooth migration, it is recommended to approach it like a developer platform launch by defining "no disruption" metrics, preparing foundational elements such as runners and networking, and rolling out changes in waves with parallel runs. The migration encompasses various layers including workflow definitions, execution, integrations, and governance, which must be moved or re-implemented carefully. Key strategies such as the use of parallel run, strangler pattern, or big bang depend on the team's risk tolerance and system architecture. Execution layers should be designed to maintain fast feedback and reliability, while identity, secrets, and governance require attention to enhance security. The migration should be piloted for parity, reliability, and developer experience before expanding in waves. Harness CI can aid in reducing migration friction by providing standardized pipeline patterns and improving build performance. After migration, focus shifts to optimization and preventing drift, with continuous improvement based on pre- and post-migration metrics.