# Usage - Distributed Coach

Coach supports the horizontal scale-out of rollout workers in distributed mode. For more information on the design and implementation of distributed Coach, see Distributed Coach - Horizontal Scale-Out. In the rest of this section, we will describe how to get started with distributed Coach.

## Interfaces and Implementations

Coach uses three interfaces to orchestrate, schedule and manager the resources of workers it spawns in the distributed mode. These interfaces are the orchestrator, memory backend and the data store. Refer to Distributed Coach - Horizontal Scale-Out for more information. The following implementation(s) are available for each interface:

- Orchestrator - Kubernetes.

- Memory Backend - Redis Pub/Sub.

- Data Store - S3 and NFS.

## Prerequisites

- Building and pushing containers - Docker.

- Container registry access for hosting container images - Docker Hub

- Using Kubernetes for orchestration - Kubernetes configuration.

- Using S3 for storing policy checkpoints - AWS CLI <https://docs.aws.amazon.com/cli/latest/userguide/installing.html>_, `AWS credentials and S3 bucket.

## Clone the Repository

    $ git clone git@github.com:NervanaSystems/coach.git
    $ cd coach

## Build Container Image and Push

Create a directory docker.

    $ mkdir docker

Create docker files in the docker directory.

A sample base docker file (Dockerfile.base) would look like this:

    FROM nvidia/cuda:9.0-cudnn7-runtime-ubuntu16.04

    ################################
    # Install apt-get Requirements #
    ################################

    # General
    RUN apt-get update && \
        apt-get install -y python3-pip cmake zlib1g-dev python3-tk python-opencv \
        # Boost libraries
        libboost-all-dev \
        # Scipy requirements
        libblas-dev liblapack-dev libatlas-base-dev gfortran \
        # Pygame requirements
        libsdl-dev libsdl-image1.2-dev libsdl-mixer1.2-dev libsdl-ttf2.0-dev \
        libsmpeg-dev libportmidi-dev libavformat-dev libswscale-dev \
        # Dashboard
        dpkg-dev build-essential python3.5-dev libjpeg-dev  libtiff-dev libsdl1.2-dev libnotify-dev \
        freeglut3 freeglut3-dev libsm-dev libgtk2.0-dev libgtk-3-dev libwebkitgtk-dev libgtk-3-dev \
        libwebkitgtk-3.0-dev libgstreamer-plugins-base1.0-dev \
        # Gym
        libav-tools libsdl2-dev swig cmake \
        # Mujoco_py
        curl libgl1-mesa-dev libgl1-mesa-glx libglew-dev libosmesa6-dev software-properties-common \
        # ViZDoom
        build-essential zlib1g-dev libsdl2-dev libjpeg-dev \
        nasm tar libbz2-dev libgtk2.0-dev cmake git libfluidsynth-dev libgme-dev \
        libopenal-dev timidity libwildmidi-dev unzip wget && \
        apt-get clean autoclean && \
        apt-get autoremove -y

    ############################
    # Install Pip Requirements #
    ############################
    RUN pip3 install --upgrade pip
    RUN pip3 install setuptools==39.1.0 && pip3 install pytest && pip3 install pytest-xdist

    RUN curl -o /usr/local/bin/patchelf https://s3-us-west-2.amazonaws.com/openai-sci-artifacts/manual-builds/patchelf_0.9_amd64.elf \
        && chmod +x /usr/local/bin/patchelf

A sample docker file for the gym environment would look like this:

    FROM coach-base:master as builder

    # prep gym and any of its related requirements.
    RUN pip3 install gym[atari,box2d,classic_control]==0.10.5

    # add coach source starting with files that could trigger
    # re-build if dependencies change.
    RUN mkdir /root/src
    COPY setup.py /root/src/.
    COPY requirements.txt /root/src/.
    RUN pip3 install -r /root/src/requirements.txt

    FROM coach-base:master
    WORKDIR /root/src
    COPY --from=builder /root/.cache /root/.cache
    COPY setup.py /root/src/.
    COPY requirements.txt /root/src/.
    COPY README.md /root/src/.
    RUN pip3 install gym[atari,box2d,classic_control]==0.10.5 && pip3 install -e .[all] && rm -rf /root/.cache
    COPY . /root/src

A sample docker file for the Mujoco environment would look like this:

    FROM coach-base:master as builder

    # prep mujoco and any of its related requirements.
    # Mujoco
    RUN mkdir -p ~/.mujoco \
        && wget https://www.roboti.us/download/mjpro150_linux.zip -O mujoco.zip \
        && unzip -n mujoco.zip -d ~/.mujoco \
        && rm mujoco.zip
    ARG MUJOCO_KEY
    ENV MUJOCO_KEY=$MUJOCO_KEY
    ENV LD_LIBRARY_PATH /root/.mujoco/mjpro150/bin:$LD_LIBRARY_PATH
    RUN echo $MUJOCO_KEY | base64 --decode > /root/.mujoco/mjkey.txt
    RUN pip3 install mujoco_py

    # add coach source starting with files that could trigger
    # re-build if dependencies change.
    RUN mkdir /root/src
    COPY setup.py /root/src/.
    COPY requirements.txt /root/src/.
    RUN pip3 install -r /root/src/requirements.txt

    FROM coach-base:master
    WORKDIR /root/src
    COPY --from=builder /root/.mujoco /root/.mujoco
    ENV LD_LIBRARY_PATH /root/.mujoco/mjpro150/bin:$LD_LIBRARY_PATH
    COPY --from=builder /root/.cache /root/.cache
    COPY setup.py /root/src/.
    COPY requirements.txt /root/src/.
    COPY README.md /root/src/.
    RUN pip3 install mujoco_py && pip3 install -e .[all] && rm -rf /root/.cache
    COPY . /root/src

A sample docker file for the ViZDoom environment would look like this:

    FROM coach-base:master as builder

    # prep vizdoom and any of its related requirements.
    RUN pip3 install vizdoom

    # add coach source starting with files that could trigger
    # re-build if dependencies change.
    RUN mkdir /root/src
    COPY setup.py /root/src/.
    COPY requirements.txt /root/src/.
    RUN pip3 install -r /root/src/requirements.txt

    FROM coach-base:master
    WORKDIR /root/src
    COPY --from=builder /root/.cache /root/.cache
    COPY setup.py /root/src/.
    COPY requirements.txt /root/src/.
    COPY README.md /root/src/.
    RUN pip3 install vizdoom && pip3 install -e .[all] && rm -rf /root/.cache
    COPY . /root/src

Build the base container. Make sure you are in the Coach root directory before building.

    $ docker build -t coach-base:master -f docker/Dockerfile.base .

If you would like to use the Mujoco environment, save this key as an environment variable. Replace <mujoco_key> with the contents of your mujoco key.

    $ export MUJOCO_KEY=<mujoco_key>

Build the container for your environment. Replace <env> with your choice of environment. The choices are gym, mujoco and doom. Replace <user-name>, <image-name> and <tag> with appropriate values.

    $ docker build --build-arg MUJOCO_KEY=${MUJOCO_KEY} -t <user-name>/<image-name>:<tag> -f docker/Dockerfile.<env> .

Push the container to a registry of your choice. Replace <user-name>, <image-name> and <tag> with appropriate values.

    $ docker push <user-name>/<image-name>:<tag>

## Create a Config file

Add the following contents to file. Replace <user-name>, <image-name>, <tag>, <bucket-name> and <path-to-aws-credentials> with appropriate values.

    [coach]
    image = <user-name>/<image-name>:<tag>
    memory_backend = redispubsub
    data_store = s3
    s3_end_point = s3.amazonaws.com
    s3_bucket_name = <bucket-name>
    s3_creds_file = <path-to-aws-credentials>

## Run Distributed Coach

The following command will run distributed Coach with CartPole_ClippedPPO preset, Redis Pub/Sub as the memory backend, S3 as the data store in Kubernetes with three rollout workers.

    $ python3 rl_coach/coach.py -p CartPole_ClippedPPO \
    -dc \
    -e <experiment-name> \
    -n 3 \
    -dcp <path-to-config-file>