Distributed tensorflow on kubernetes

Distributed TensorFlow

on Kubernetes

資訊與通訊研究所蔣是文 Mac Chiang

Copyright 2017 ITRI 工業技術研究院

Agenda

• Kubernetes Introduction

• Scheduling GPUs on Kubernetes

• Distributed TensorFlow Introduction

• Running Distributed TensorFlow on Kubernetes

• Experience Sharing

• Summary

2


What’s Kubernetes

• “Kubernetes” is Greek for captain or pilot

• Experiences from Google and design by Goolge

• Kubernetes is a production-grade, open-source platform that orchestrates the placement (scheduling) and execution of application containers within and across computer clusters.

• Masters manage the cluster and the nodes are used to host the running applications.

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Why Kubernetes

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• Automatic binpacking

• Horizontal scaling

• Automated rollouts and rollback

• Service monitor

• Self-healing

• Service discovery and load balancing

• 100% Open source, written in Go


Scheduling GPUs on Kubernetes

• Nvidia drivers are installed

• Turned on alpha feature gate Accelerators across the system▪ --feature-gates="Accelerators=true“

• Nodes must be using docker engine as the container runtime

5


Scheduling GPUs on Kubernetes (cont.)

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apiVersion: v1

kind: Pod

metadata:

name: gpu-pod

spec:

containers:

-

name: gpu-container-1

image: gcr.io/google_containers/pause:2.0

resources:

limits:

alpha.kubernetes.io/nvidia-gpu: 2 # requesting 2 GPUs

-

name: gpu-container-2

image: gcr.io/google_containers/pause:2.0

resources:

limits:

alpha.kubernetes.io/nvidia-gpu: 3 # requesting 3 GPUs


Scheduling on Different GPU Versions

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• Labeling nodes with GPU HW type

• Specify the GPU types via Node Affinity rules

Tesla P100

Node1 Node2

2 * K80 1 * P100

Tesla K80

gpu:k80 gpu:p100


Access to CUDA libraries from Docker

nvidia-driver

libcuda.so

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TensorFlow

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• Originally developed by the Google Brain Team within Google's Machine Intelligence research organization

• An open source software library for numerical computation using data flow graphs

• Nodes in the graph represent mathematical operations, while the graph edges represent the multidimensional data arrays (tensors) communicated between them.

• Support one or more CPUs or GPUs in a desktop, server, or mobile device with a single API


Distributed TensorFlow

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http://www.inwinstack.com/index.php/zh/2017/04/17/tensorflow-on-kubernetes/


Distributed TensorFlow (cont.)

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• Replication▪ In-graph

▪ Between-graph

• Training▪ Asynchronous

▪ Synchronous


Distributed TensorFlow on K8S

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• TensorFlow ecosystem▪ https://github.com/tensorflow/ecosystem

https://github.com/tensorflow/ecosystem


Distributed TensorFlow on K8S (cont.)

13

• Prepare codes for distributed training▪ Flags for configuring the task

▪ Construct the cluster and start the server

▪ Set the device before graph construction

# Flags for configuring the task

flags.DEFINE_integer("task_index", None,

"Worker task index, should be >= 0. task_index=0 is "

"the master worker task the performs the variable "

"initialization.")

flags.DEFINE_string("ps_hosts", None,

"Comma-separated list of hostname:port pairs")

flags.DEFINE_string("worker_hosts", None,

"Comma-separated list of hostname:port pairs")

flags.DEFINE_string("job_name", None, "job name: worker or ps")

# Construct the cluster and start the server

ps_spec = FLAGS.ps_hosts.split(",")

worker_spec = FLAGS.worker_hosts.split(",")

cluster = tf.train.ClusterSpec({

"ps": ps_spec,

"worker": worker_spec})

server = tf.train.Server(

cluster, job_name=FLAGS.job_name,

task_index=FLAGS.task_index)

if FLAGS.job_name == "ps":

server.join()

with tf.device(tf.train.replica_device_setter(

worker_device="/job:worker/task:%d" % FLAGS.task_index, Cluster=cluster)):

# Construct the TensorFlow graph.

# Run the TensorFlow graph.



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• Build docker image▪ Prepare Dockerfile

▪ Build docker image

docker build -t <image_name>:v1 -f Dockerfile .

docker build -t macchiang/mnist:v7 -f Dockerfile .

docker push <image_name>:v1 Push image to docker hub

docker push macchiang/mnist:v7

FROM tensorflow/tensorflow:latest-gpu

COPY mnist_replicatensorflow/tensorflow.py /

ENTRYPOINT ["python", "/mnist_replica.py"]



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• My revised history▪ https://hub.docker.com/r/macchiang/mnist/tags/

https://hub.docker.com/r/macchiang/mnist/tags/



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• Specify parameters in jinja template file▪ name, image, worker_replicas, ps_replicas, script, data_dir, and train_dir

▪ You may optionally specify credential_secret_name and

credential_secret_key if you need to read and write to Google Cloud

Storage

• Generate K8S YAML and create services and pods▪ python render_template.py mnist.yaml.jinja | kubectl create -f -

command:

- "/root/inception/bazel-bin/inception/imagenet_distributed_train"

args:

- "--data_dir=/data/raw-data"

- "--task_index=0"

- "--job_name=worker“

- "--worker_hosts=inception-worker-0:5000,inception-worker-1:5000“

- "--ps_hosts=inception-ps-0:5000"



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Worker0

Worker1

Service Worker0

Service Worker1

:5000

PS0

Service PS0

:5000

:5000

Training Data

NFS

Training Result

NFS

Read

Write


Distributed Tensorflow with CPUs

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Container Orchestration Platform

35 Nodes

ImageNet Data

(145GB)

NFS

Training Result

NFS

2* Intel(R) Xeon(R) CPU E5620 @ 2.40GHz

48GB Memory

• Inception Model▪ Spent 9.23 days

35 Containers

Rethinking the Inception Architecture for Computer Vision


Summary

• Kubernetes▪ Production-grade container orchestration platform

▪ GPU resources management

a. Nvidia GPU only now

b. In Kuberntest 1.8, you can use NVIDIA device plugin.

» https://github.com/NVIDIA/k8s-device-plugin

• Kubernetes + Distributed TensorFlow▪ Easy to build the distributed training cluster

▪ Leverage Kubernetes advantages

a. Restart failed container

b. Monitoring

c. Scheduling

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https://github.com/NVIDIA/k8s-device-plugin

Thank you!

[email protected]

Kubernetes Taiwan User Group

Distributed tensorflow on kubernetes

Technology

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