Hi, yes this max_run is for anything running in SageMaker Training (HF DLC, but also built-in algos, other framework containers like Scikit, XGBoost, etc and bring-your-own docker)
It is an optional parameter of the Python SDK Estimators, set by default to 86400s (1 day). Customer code (including HF) most often takes less than a day to run, which is why people don’t know about that parameter and rarely override it.