Controller

This component implements a state machine to schedule the containers in a learner pod, and updates Zookeeper about the status of the job.

The current state of the state machine is in a file called $JOB_STATE_DIR/current_state. Files in the $JOB_STATE_DIR are used to trigger the other containers in the pod, and to record the completion of the other containers.

State machine

The transitions in the state machine are documented in the ./docs/state-machine.dot file.

To build a visual representation of the state machine:

$ make docs

The output is in the ./docs/state-machine.pdf file.