GRPO

AWS published a technical guide on designing custom composite reward functions for multi-turn reinforcement fine-tuning (RFT) of Amazon Nova models via Nova Forge's Bring Your Own Orchestration (BYOO) capability. The post covers GRPO-based reward scoring, combining outcome rewards, behavioral rewards, and penalties, plus a serverless multi-turn RL option now generally available.

AWS has released infrastructure for deploying multi-turn reinforcement learning to train Amazon Nova models on SageMaker HyperPod. The system requires a minimum of 10 ml.p5.48xlarge instances and costs approximately $786-$1,180 per hour when running.