Developed and integrated the Nova External Scheduler API within the sapcc/nova repository, enabling policy-driven host selection by delegating ordering and filtering decisions to an external service after initial filtering and weighing. Focused on backend development and API integration using Python, the work introduced configurable external API endpoints and timeout settings to support flexible scheduling strategies. The implementation wired external scheduler invocation directly into the placement path, allowing dynamic reordering and filtering of hosts before instance placement. This feature established a foundation for extensible scheduling policies, aiming to improve resource utilization and support service level agreement optimization in cloud computing environments.