IFM open-sources RL360: 8,192 concurrent sandboxes and ~1.3M rollouts for agentic RL

rupspace · x · 2026-10-23

IFM has open-sourced RL360, the post-training infrastructure behind K2 Horizon's six domain experts: 8,192 concurrent sandboxes, 150 steps over 7 days, and 1.3M rollouts.

The core insight: in long-horizon agentic RL, thousands of agents run in real sandboxes on multi-minute tasks, and mid-task sandbox crashes arrive with the same low score as a wrong answer—penalizing the model for system failures. At this scale, IFM argues, distinguishing environment failures from model failures becomes part of the learning algorithm itself.

RL360 is modular: Miles handles rollouts and optimization, Harbor manages agent environments, SGLang serves inference, and Megatron-LM runs training—each component scaling independently. The team also shared what broke at scale and what they learned; code and run instructions are on GitHub (Apache-2.0).

Related event: IFM Open-Sources RL360, Infrastructure Behind K2 Horizon RL Training(3 posts)→

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