Yahoo uses Hadoop clusters separately from deep learning clusters to avoid unnecessary data movement. YARN works well for deep learning, allowing multiple experiments to run concurrently on a single cluster in a cost-effective manner. Previously, GPU resources were manually scheduled using a notepad, which was painful and only worked for a small number of users. The document discusses retraining an Inception-v3 model on 3 specific categories in ~30 minutes on a desktop CPU with over 90% accuracy. It also mentions using one server per task and tools for distributed TensorFlow that summarize logs and initialize from checkpoints.