Meta AI Open-Sources Rebalancer: C++ Assignment Solver Running 40 Million Placement Problems Daily

Meta AI has open-sourced Rebalancer, a high-performance C++ assignment solver that runs approximately 40 million resource placement and scheduling problems per day within Meta's production infrastructure. The tool is designed to optimize large-scale workload distribution across compute clusters, addressing the kind of combinatorial assignment problems that arise in fleet management, data center scheduling, and distributed systems. For infrastructure engineers and developers managing large-scale deployments, Rebalancer offers a battle-tested, production-grade solver that has been validated at one of the world's largest compute scales. Open-sourcing it gives the broader community access to Meta's internal scheduling logic, which could be adapted for cloud resource optimization, job scheduling, and similar systems problems. The release reflects Meta's continued investment in open-sourcing infrastructure tooling alongside its AI model work.