Amazon Web Services (AWS) has announced the general availability of serverless training sessions for Amazon SageMaker AI. This expansion aims to simplify the process of customizing open-weight foundation models by removing the need for users to manage complex GPU clusters or infrastructure configurations.
Streamlining model customization
Customizing AI models to fit specific business needs—such as adapting to specialized clinical vocabulary, product catalogs, or internal workflows—often requires significant infrastructure overhead. Previously, developers were responsible for selecting instance types and managing distributed training environments. With the new serverless training sessions, AWS manages GPU allocation, distributed execution, fault recovery, and checkpoint storage.
The platform supports a variety of post-training techniques, including Supervised Fine-Tuning (SFT), Direct Preference Optimization (DPO), and various forms of reinforcement learning. According to the announcement, users maintain control over the training logic, such as custom loss functions and reward signals, while SageMaker handles the operational complexity.
Focus on agentic workflows
A key focus of this release is supporting multi-turn reinforcement learning, which is increasingly vital for training AI agents capable of completing complex, multi-step tasks like booking travel or triaging support tickets. Training sessions allow users to define their own RL stages and reward signals within a single, managed loop.
By integrating with development environments like SageMaker Studio, GitHub Copilot, and Claude Code, developers can use an available “training sessions cookbook” to guide the data preparation, training, and deployment processes. Users pay only for the compute tokens processed during the training session, with the meter pausing when the user’s reward function scores a batch.
Governance and security
AWS emphasized that this serverless approach maintains strict data security standards. Customers utilize their own AWS Identity and Access Management (IAM) roles, virtual private clouds (VPC), and AWS Key Management Service (AWS KMS) keys. Data remains within the customer’s specified Amazon S3 buckets, and AWS explicitly states that customer data and customized model weights are not used to train other models.
At launch, the service supports several prominent models, including gpt-oss-20b, gemma-4-31B-it, and Qwen3.6-27B and Qwen3.8-27B. Before deploying customized models into production, users are encouraged to utilize integrated evaluation tools for bias and safety checks, with ongoing monitoring provided through Amazon CloudWatch.
Source: aws.amazon.com
Original article: https://aws.amazon.com/blogs/machine-learning/announcing-new-ways-to-customize-models-with-sagemaker-ai-without-managing-gpus/

