Ray Train Architecture#

A diagram of the Ray Train architecture is provided below.

../_images/train-arch.svg

Trainer#

The Trainer is the main class that is exposed in the Ray Train API that users will interact with.

  • The user will pass in a function which defines the training logic.

  • The Trainer will create an Executor to run the distributed training.

  • The Trainer will handle callbacks based on the results from the BackendExecutor.

Executor#

The executor is an interface which handles execution of distributed training.

  • The executor will handle the creation of an actor group and will be initialized in conjunction with a backend.

  • Worker resources, number of workers, and placement strategy will be passed to the Worker Group.

Backend#

A backend is used in conjunction with the executor to initialize and manage framework-specific communication protocols. Each communication library (Torch, Horovod, TensorFlow, etc.) will have a separate backend and will take a specific configuration value.

WorkerGroup#

The WorkerGroup is a generic utility class for managing a group of Ray Actors.

  • This is similar in concept to Fiber’s Ring.