Kubernetes Custom Resource and Operator for PyTorch jobs

Overview

This repository contains the specification and implementation of PyTorchJob custom resource definition. Using this custom resource, users can create and manage PyTorch jobs like other built-in resources in Kubernetes. See CRD definition

Prerequisites

• Kubernetes >= 1.8
• kubectl

Installing PyTorch Operator

Please refer to the installation instructions in the Kubeflow user guide. This installs pytorchjob CRD and pytorch-operator controller to manage the lifecycle of PyTorch jobs.

Creating a PyTorch Job

You can create PyTorch Job by defining a PyTorchJob config file. See distributed MNIST example config file. You may change the config file based on your requirements.

cat examples/tcp-dist/mnist/v1alpha2/pytorch_job_mnist.yaml

Deploy the PyTorchJob resource to start training:

kubectl create -f examples/tcp-dist/mnist/v1alpha2/pytorch_job_mnist.yaml

You should now be able to see the created pods matching the specified number of replicas.

kubectl get pods -l pytorch_job_name=pytorch-tcp-dist-mnist

Training should run for about 10 epochs and takes 5-10 minutes on a cpu cluster. Logs can be inspected to see its training progress.

PODNAME=$(kubectl get pods -l pytorch_job_name=pytorch-tcp-dist-mnist,task_index=0 -o name)
kubectl logs -f ${PODNAME}

Monitoring a PyTorch Job

kubectl get -o yaml pytorchjobs pytorch-tcp-dist-mnist

See the status section to monitor the job status. Here is sample output when the job is successfully completed.

apiVersion: v1
items:
- apiVersion: kubeflow.org/v1alpha2
  kind: PyTorchJob
  metadata:
    clusterName: ""
    creationTimestamp: 2018-09-14T14:31:02Z
    generation: 1
    labels:
      app.kubernetes.io/deploy-manager: ksonnet
    name: pytorch-tcp-dist-mnist
    resourceVersion: "21599007"
    selfLink: /apis/kubeflow.org/v1alpha2/namespaces/kubeflow/pytorchjobs/pytorch-tcp-dist-mnist
    uid: ce70c8de-b82a-11e8-8b09-42010aa000d2
  spec:
    cleanPodPolicy: None
    pytorchReplicaSpecs:
      Master:
        replicas: 1
        restartPolicy: OnFailure
        template:
          metadata:
            creationTimestamp: null
          spec:
            containers:
            - image: johnugeorge/pytorch-tcp-mnist:3.0
              name: pytorch
              ports:
              - containerPort: 23456
                name: pytorchjob-port
              resources: {}
      Worker:
        replicas: 3
        restartPolicy: OnFailure
        template:
          metadata:
            creationTimestamp: null
          spec:
            containers:
            - image: johnugeorge/pytorch-tcp-mnist:3.0
              name: pytorch
              ports:
              - containerPort: 23456
                name: pytorchjob-port
              resources: {}
  status:
    completionTime: 2018-09-14T14:33:13Z
    conditions:
    - lastTransitionTime: 2018-09-14T14:31:02Z
      lastUpdateTime: 2018-09-14T14:31:02Z
      message: PyTorchJob pytorch-tcp-dist-mnist is created.
      reason: PyTorchJobCreated
      status: "True"
      type: Created
    - lastTransitionTime: 2018-09-14T14:31:02Z
      lastUpdateTime: 2018-09-14T14:31:05Z
      message: PyTorchJob pytorch-tcp-dist-mnist is running.
      reason: PyTorchJobRunning
      status: "False"
      type: Running
    - lastTransitionTime: 2018-09-14T14:31:02Z
      lastUpdateTime: 2018-09-14T14:33:13Z
      message: PyTorchJob pytorch-tcp-dist-mnist is successfully completed.
      reason: PyTorchJobSucceeded
      status: "True"
      type: Succeeded
    pytorchReplicaStatuses:
      Master: {}
      Worker: {}
    startTime: 2018-09-14T14:31:04Z
kind: List
metadata:
  resourceVersion: ""
  selfLink: ""